Remove disabled buttons and update Destination flows to reflect read-only state

[qreshi]

Description

Changes in this PR:

• Disable all fields when viewing Destinations/Email Groups/Email Accounts since they are in a read-only state now
• Since Destinations have been deprecated, certain actions were disabled, this PR removes buttons that were disabled and changes options from edit to view to better convey the read-only state
• Fixes a bug where editing an existing Monitor didn't correctly populate channels
• Shows the banner of Notification plugin not being installed from the Destinations list page when applicable

Note: There are some dangling code paths now (some onCreate() and onDelete()s that are behind removed actions/buttons and routes for the removed Destination API, etc.). These can be removed in follow-up PRs since it's not user accessible.

Issues Resolved

Related to opensearch-project/alerting#105

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov-commenter]

Codecov Report

Merging #221 (7792fce) into main (fbea210) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #221      +/-   ##
==========================================
- Coverage   53.22%   53.20%   -0.03%     
==========================================
  Files         211      209       -2     
  Lines        5257     5250       -7     
  Branches      710      710              
==========================================
- Hits         2798     2793       -5     
+ Misses       2457     2455       -2     
  Partials        2        2              

Impacted Files	Coverage Δ
...ions/components/createDestinations/Email/Sender.js	13.63% <0.00%> (ø)
...ns/containers/DestinationsList/DestinationsList.js	52.94% <0.00%> (ø)
...s/components/createDestinations/Webhook/Webhook.js	30.00% <0.00%> (ø)
.../components/createDestinations/Email/EmailGroup.js	13.63% <0.00%> (ø)
.../containers/CreateDestination/CreateDestination.js	3.79% <0.00%> (ø)
...onents/createDestinations/CustomWebhook/URLInfo.js	16.00% <0.00%> (ø)
...iners/CreateDestination/EmailSender/EmailSender.js	2.85% <0.00%> (ø)
...s/CreateDestination/ManageSenders/ManageSenders.js	43.47% <0.00%> (ø)
...tificationsInfoCallOut/NotificationsInfoCallOut.js	100.00% <0.00%> (ø)
...eateDestination/EmailRecipients/EmailRecipients.js	2.43% <0.00%> (ø)
... and 6 more

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