fix(W-17812967): Heroku-cli-command: Header overflow

[justinwilaby]

This PR fixes the accumulation of requestIds in the header causing a header overflow error in long running poll operations. These have been observed to be larger than 8k (Node default max) in commands such as pg:wait

This PR limits the Request-Id header size to 7k which allows 1k for other header data. If the 7k limit is exceeded, the Request-Id is stripped of all previous values and is started over.

Note that a side effect of this is that long running poll operations now have the potential of fracturing the API call 'story' in tracking data.

test

1. build & pack (npm run build && npm pack)
2. install the packed tarball in the Heroku CLI project
3. comment out the break statement in packages/cli/src/commands/ps/wait.ts
4. run the command and let it go a while
5. OBSERVE - no header overflow is seen

[k80bowman]

Could you please add a unit test or two to cover this logic? Also, since this logic touches a lot of what the CLI does, are there other commands we should be testing to make sure this change doesn't have unintended consequences?

[eablack]

Nice job including comments to explain why this logic is in place.

[k80bowman]

Thank you for adding the tests