[cadence/debug] Update polletracker to support poller type breakdown

[ketsiambaku]

What changed?
We use the PollerTracker interface to count the number of running pollers and we display it internal in a debug page.
This change is updating the interface and its usage so that the poller count is broken down by worker type (e.g: activity, workflow, shadow, localactivity, etc.)

Why?
The break down gives a better insight on the running instance

How did you test it?
unit tests

Potential risks

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.52%. Comparing base (e3802b7) to head (65fdc1b).
⚠️ Report is 63 commits behind head on master.

Files with missing lines	Coverage Δ
internal/common/debug/workerstats_noop.go	100.00% <100.00%> (ø)
internal/internal_worker_base.go	83.41% <100.00%> (+1.46%)	⬆️

... and 1 file with indirect coverage changes

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