Add team_name tag to remaining multi-team metrics

[Tegh25]

Should be able to close #68294 after merge.

Follow-up to #68367, #68589, #68593, #68594, #68599, #68108, and #68601.

Primary Changes

Added team_name tag to the following:
connection_test.reaped
connection_test.success
connection_test.failed
connection_test.hook_duration
scheduler.executor_heartbeat_duration
triggers.blocked_main_thread

Added a team_name field to TestConnection class. This is to share team_name from the scheduler to connection test supervisor without changing the execution API.

Excerpt from comment on closing issue:

The remaining scope was identified by @ferruzzi and is completed in this PR.

Remaining work (6)

Team-attributable, emit site has a team identity, but no team_name tag yet:

• connection_test.reaped (scheduler reaper; ct.team_name is literally in scope and logged one line above the stats.incr, only prior_state is tagged)
• connection_test.success (worker connection-test supervisor; per connection-test row)
• connection_test.failed (same)
• connection_test.hook_duration (same)
• scheduler.executor_heartbeat_duration (loops over self.executors; each executor.team_name is available, tagged only by executor class)
• triggers.blocked_main_thread (emitted in a team-scoped triggerer's TriggerRunner; team_name lives on the runner/supervisor but is not plumbed to this emit)

Two of these are more borderline than the others: scheduler.executor_heartbeat_duration
and triggers.blocked_main_thread are component-level (team-scoped executor /
team-scoped triggerer). They satisfy the signal list, but if those components are
considered "shared," they'd drop to non-team. The four connection_test.* rows are
clean Remaining items per the explicit "connection-test row" signal.

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[ferruzzi]

Looks good to me, thanks! I left two small notes before I'll approve. Those were solid catches on the out of date docs, but they shouldn't be lumped in with this change. Split them into a new PR and I'll approve both.

[Tegh25]

Hi @ferruzzi, thank you. I reverted the doc changes and added them to a new PR at #70146.

[ferruzzi]

Commented on the other PR; too far :P

The connection tests bullet and the scheduler.executor_heartbeat_duration / triggers.blocked_main_thread additions to the existing triggerer/executor bullets were directly related to this PR and should have stayed. The changes that were just "I noticed this while I was in here" should be moved out.

Sorry for the confusion.

[Tegh25]

My bad. I amended the commit to include only the relevant doc changes, lmk what you think

[ferruzzi]

Approved pending CI passing