Notify telemetry only every second about the tx pool status

[bkchr]

Before this was done for every imported transaction. When a lot of transactions got imported, the import notification channel was filled. The underlying problem was that the status call is read locking the validated_pool which will be write locked by the internal submitting logic. Thus, the submitting and status reading was interferring which each other.

[michalkucharczyk]

for the record: https://github.com/paritytech/polkadot-sdk/issues/6600#issuecomment-2493054558

[bkchr]

/cmd prdoc --audience node_operator --bump patch