* `txthrottler`: move `ThrottlerInterface` to `go/vt/throttler`, use `slices` pkg, add stats (vitessio#16248)

Signed-off-by: Tim Vaillancourt <[email protected]>

* revert to `reflect`

Signed-off-by: Tim Vaillancourt <[email protected]>

* Support passing filters to `discovery.NewHealthCheck(...)`

Signed-off-by: Tim Vaillancourt <[email protected]>

* Update go/vt/vttablet/tabletserver/txthrottler/tx_throttler.go

Co-authored-by: Matt Lord <[email protected]>
Signed-off-by: Tim Vaillancourt <[email protected]>

* Address some PR suggestions

Signed-off-by: Tim Vaillancourt <[email protected]>

* PR ctx suggestion

Signed-off-by: Tim Vaillancourt <[email protected]>

* fix test

Signed-off-by: Tim Vaillancourt <[email protected]>

* simplify updateHealthCheckCells signature

Signed-off-by: Tim Vaillancourt <[email protected]>

* Fix race in `replicationLagModule` of `go/vt/throttle`

Signed-off-by: Tim Vaillancourt <[email protected]>

---------

Signed-off-by: Tim Vaillancourt <[email protected]>
Co-authored-by: Matt Lord <[email protected]>