[Pipe] Back off TsFile parser admission retries

[Caideyipi]

Description

TsFile parser admission currently retries with a fixed sleep when Pipe memory is exhausted. Concurrent parser requests can therefore wake in lockstep, and a request may keep sleeping even after another parser releases its reservation.

This PR changes parser admission retries to:

• use bounded exponential backoff starting from pipe_check_memory_enough_interval_ms;
• cap the interval at the initial interval multiplied by pipe_memory_allocate_max_retries;
• add 50%-100% jitter to avoid synchronized retries;
• wait on PipeMemoryManager so parser and Pipe memory releases wake admission attempts immediately;
• preserve the existing overall parser admission timeout.

This is independent of receiver/sink backoff in #18236, which does not cover parser admission. Fair scheduling across Pipes remains isolated in #18260.

Tests

• Verify exponential growth, overflow-safe capping, and jitter bounds.
• Exhaust parser memory with a real TsFile parser request, configure a 10-second retry interval, release one reservation, and verify the parser is notified and admitted within 3 seconds.

---

This PR has:

• been self-reviewed.
  • concurrent read and write
• added unit tests for parser admission backoff and release notification.

---

Key changed/added classes

• PipeTsFileInsertionEvent
• PipeMemoryManager
• PipeTsFileInsertionEventAdmissionTest

[jt2594838]

If the semantic of the maxRetries has changed, you should supplement some description in the config.