[Desktop] Add error logging to view server errors in brave://rewards-internals page

[LaurenWags]

Description

On brave://rewards-internals page would be great to have a way to show any errors returned from the server that are currently only visible in terminal logs.

Steps to Reproduce

1. Have Rewards enabled
2. Encounter some error that is only visible in the terminal logs (perhaps server is returning some error)
3. Be confused Rewards is not behaving as you expect, but you have no idea why

Actual result:

No way to see any debugging info in the UI

Expected result:

Be able to go to a page like brave://rewards-internals and see an "errors" section (or similar) that lists errors (maybe only going back X number of days), as well as date/time stamp. Perhaps including request/response might be useful as well.

cc @NejcZdovc for consideration

[NejcZdovc]

And not just network, but output from shared libs as well. This should be split between ads and rewards, so that user can load one or another in internals page. I think this needs to be recorded in a file and be per session for example.

[tmancey]

Discussed with privacy team and the log should be deleted when clearing browsing history and not log any diagnostic information when private browsing

[LaurenWags]

Verified passed using 1.11.91 and

Brave	1.11.92 Chromium: 84.0.4147.68 (Official Build) dev (64-bit)
Revision	e7b7234037639b407e69c5428c891ce018cd6c0d-refs/branch-heads/4147@{#772}
OS	macOS Version 10.14.6 (Build 18G3020)

• Verified test plan from Implement and expose diagnostic logging for Brave Rewards in the UI brave-core#5600
• Confirmed Rewards.log is written to the user profile Default folder
• Confirmed Rewards.log is curtailed to the last 20,000 lines when restarting the browser
• Confirmed able to auto-refresh log in brave://rewards-internals (refresh every 5s checkbox works)
• Confirmed able to refresh log in brave://rewards-internals
• Confirmed Rewards.log is curtailed to the last 20,000 lines when the log exceeds 10mb
• Confirmed able to download log from the download button on brave://rewards-internals
• Confirmed able to clear log in brave://rewards-internals
• Confirmed after clearing the logs, and then generating some log messages (tip, etc), I was able to view logs again. The cleared logs did not display on brave://rewards-internals or in Rewards.log file.
• Spot checked logs for various expected messaging (balance calls for restored wallet, tip information, etc)
• No obvious performance regressions noted (have been using Beta 1.11.x on personal profile for several weeks and didn't notice perf issues).

Verification passed on

Brave	1.11.94 Chromium: 84.0.4147.85 (Official Build) (64-bit)
Revision	e20c13e958edc3707db3d26d513780a7f6331a4b-refs/branch-heads/4147@{#837}
OS	Ubuntu 18.04 LTS

• Verified test plan from Implement and expose diagnostic logging for Brave Rewards in the UI brave-core#5600
• Confirmed Rewards.log is written to the user profile Default folder
• Confirmed Rewards.log is curtailed to the last 20,000 lines when restarting the browser
• Confirmed able to auto-refresh log in brave://rewards-internals (refresh every 5s checkbox works)
• Confirmed able to refresh log in brave://rewards-internals
• Confirmed Rewards.log is curtailed to the last 20,000 lines when the log exceeds 10mb
• Confirmed able to download log from the download button on brave://rewards-internals
• Confirmed able to clear log in brave://rewards-internals
• Confirmed after clearing the logs, and then generating some log messages (tip, etc), I was able to view logs again. The cleared logs did not display on brave://rewards-internals or in Rewards.log file.
• Spot checked logs for various expected messaging (balance calls for restored wallet, tip information, etc)

---

Verification passed on

Brave | 1.11.96 Chromium: 84.0.4147.89 (Official Build) (64-bit)
-- | --
Revision | 19abfe7bcba9318a0b2a6bc6634a67fc834aa592-refs/branch-heads/4147@{#852}
OS | Windows 10 OS Version 1903 (Build 18362.900)

• Verified test plan from Implement and expose diagnostic logging for Brave Rewards in the UI brave-core#5600
• Verified test plan from Implement and expose diagnostic logging for Brave Rewards in the UI brave-core#5600
• Confirmed Rewards.log is written to the user profile Default folder
• Confirmed Rewards.log is curtailed to the last 20,000 lines when restarting the browser
• Confirmed able to auto-refresh log in brave://rewards-internals (refresh every 5s checkbox works)
• Confirmed able to refresh log in brave://rewards-internals
• Confirmed Rewards.log is curtailed to the last 20,000 lines when the log exceeds 10mb
• Confirmed able to download log from the download button on brave://rewards-internals
• Confirmed able to clear log in brave://rewards-internals
• Confirmed after clearing the logs, and then generating some log messages (tip, etc), I was able to view logs again. The cleared logs did not display on brave://rewards-internals or in Rewards.log file.
• Spot checked logs for various expected messaging (balance calls for restored wallet, tip information, etc)

[LaurenWags]

Per discussion with @srirambv removed OS/Android tag and logged android specific issue - #10712