web-api: prevent apps.event.authorizations.list API from ever sending token in the body

[filmaj]

Sending token in the body for the apps.event.authorizations.list API will cause the API to return an error (see the last sentence in this doc).

This fixes #1498.

Additionally, this PR compiles all headers when logging them out in debug mode - even the ones axios sets by default. This critically also includes the token if the token is passed in to WebClient constructor. I made this change and included it here as otherwise determining the full list of headers sent by web-api was challenging. Optionally, this logging feature can be removed if people have opinions about it. Previously, the debug output would look like this:

[DEBUG]  web-api:WebClient:0 apiCall('apps.event.authorizations.list') start
[DEBUG]  web-api:WebClient:0 http request url: https://slack.com/api/apps.event.authorizations.list
[DEBUG]  web-api:WebClient:0 http request body: {"event_context":"4-eyJldCI6Im1lc3NhZ2UiLCJ0aWQiOiJUMDI5VjY0NjhSTCIsImFpZCI6IkEwNjAxUkVRTDkzIiwiY2lkIjoiQzAyOVlUNUtFTUIifQ"}
[DEBUG]  web-api:WebClient:0 http request headers: {}

Note the request headers are stated to be empty (when passing a token into the WebClient constructor). Impossible, as the token needs to be provided SOMEHOW!

With the logging changes introduced in this PR, the same call as above now yields:

[DEBUG]  web-api:WebClient:0 apiCall('apps.event.authorizations.list') start
[DEBUG]  web-api:WebClient:0 http request url: https://slack.com/api/apps.event.authorizations.list
[DEBUG]  web-api:WebClient:0 http request body: {"event_context":"4-eyJldCI6Im1lc3NhZ2UiLCJ0aWQiOiJUMDI5VjY0NjhSTCIsImFpZCI6IkEwNjAxUkVRTDkzIiwiY2lkIjoiQzAyOVlUNUtFTUIifQ"}
[DEBUG]  web-api:WebClient:0 http request headers: {"User-Agent":"@slack:web-api/7.0.1 node/18.15.0 darwin/23.2.0","Authorization":"[[REDACTED]]","Accept":"application/json, text/plain, */*"}

[seratch]

Thanks for fixing this!