storagenode/piecestore: Only limit grpc requests

[isaachess]

What: Remove connection limits for drpc requests. drpc requests will continue to add to the limit, and grpc requests will respect the limit, but drpc requests will continue regardless of what the value of the current requests is.

Why: With drpc in place we no longer need to limit request limits.

Please describe the tests:

• Test 1: The current test checking for concurrent limits is skipped because it is flaky. I don't see it within the scope of this ticket to fix that.

Please describe the performance impact:

Code Review Checklist (to be filled out by reviewer)

• Does the PR describe what changes are being made?
• Does the PR describe why the changes are being made?
• Does the code follow our style guide?
• Does the code follow our testing guide?
• Is the PR appropriately sized? (If it could be broken into smaller PRs it should be)
• Does the new code have enough tests? (every PR should have tests or justification otherwise. Bug-fix PRs especially)
• Does the new code have enough documentation that answers "how do I use it?" and "what does it do?"? (both source documentation and higher level, diagrams?)
• Does any documentation need updating?
• Do the database access patterns make sense?

[zeebo]

Wow, super lucky that upload had two different entry points and we only care to limit uploads. I thought this was going to be way harder and gross lol.

[isaachess]

@zeebo I know right? I was prepared for it to be nasty as well, but it ended up being simple to limit one but not the other.

[simongui]

Nice! I thought this was going to be uglier as well. Good job! Thanks for renaming the variable to liveGRPCRequests so it's a bit more clear to the next random person in here 😄

[jtolio]

doesn't that mean this is still just liveRequests?

[jtolio]

Nice! I thought this was going to be uglier as well. Good job! Thanks for renaming the variable to liveGRPCRequests so it's a bit more clear to the next random person in here smile

but it includes live drpc requests too, right? it's a counter of all live requests, regardless