Optimize LLO transmitter queue deletes using batching

[samsondav]

- This reduces required number of DB connections and should reduce
  overall DB transaction load
- The server doesn't need to be aware of DB deletion at all, the
  persistence manager now handles all of it

[github-actions]

I see you updated files related to core. Please run pnpm changeset in the root directory to add a changeset as well as in the text include at least one of the following tags:

• #added For any new functionality added.
• #breaking_change For any functionality that requires manual action for the node to boot.
• #bugfix For bug fixes.
• #changed For any change to the existing functionality.
• #db_update For any feature that introduces updates to database schema.
• #deprecation_notice For any upcoming deprecation functionality.
• #internal For changesets that need to be excluded from the final changelog.
• #nops For any feature that is NOP facing and needs to be in the official Release Notes for the release.
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🎖️ No JIRA issue number found in: PR title, commit message, or branch name. Please include the issue ID in one of these.

[cl-sonarqube-production]

Quality Gate passed

Issues
1 New issue
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube

[github-actions]

AER Report: CI Core

aer_workflow , commit , Detect Changes , Clean Go Tidy & Generate , Scheduled Run Frequency , Core Tests (go_core_tests) , GolangCI Lint (.) , Core Tests (go_core_tests_integration) , test-scripts , Core Tests (go_core_ccip_deployment_tests) , Core Tests (go_core_fuzz) , Core Tests (go_core_race_tests) , lint , SonarQube Scan

1. Linting error: defer inside loops

Job ID: Golang Lint (.)

Source of Error:

core/services/llo/mercurytransmitter/persistence_manager.go:128:4: defer: prefer not to defer inside loops (revive)
			defer cancel()
			^

Why: The revive linter detected a defer statement inside a loop, which is generally discouraged because it can lead to resource leaks or unexpected behavior.

Suggested fix: Move the defer cancel() statement outside the loop or ensure it is only called once per loop iteration.

2. Test failure: Condition never satisfied

Job ID: Run tests

Source of Error:

testutils.go:341: 
	Error Trace:	/home/runner/work/chainlink/chainlink/core/internal/testutils/testutils.go:341
	 				/home/runner/work/chainlink/chainlink/core/internal/testutils/testutils.go:365
	 				/home/runner/work/chainlink/chainlink/core/services/llo/mercurytransmitter/persistence_manager_test.go:70
	Error: 	Condition never satisfied
	Test: 	TestPersistenceManagerAsyncDelete
logger.go:146: 2025-01-31T16:54:52.252Z	ERROR	LLOPersistenceManager	mercurytransmitter/persistence_manager.go:194	Failed to prune transmit requests table	{"version": "unset@unset", "serverURL": "wss://example.com/mercury", "err": "llo orm: failed to prune transmissions: context canceled"}
github.com/smartcontractkit/chainlink/v2/core/services/llo/mercurytransmitter.(*persistenceManager).runPruneLoop.func1
	/home/runner/work/chainlink/chainlink/core/services/llo/mercurytransmitter/persistence_manager.go:194
github.com/smartcontractkit/chainlink/v2/core/services/llo/mercurytransmitter.(*persistenceManager).runPruneLoop
	/home/runner/work/chainlink/chainlink/core/services/llo/mercurytransmitter/persistence_manager.go:198
FAIL

Why: The test TestPersistenceManagerAsyncDelete failed because a condition was never satisfied, likely due to the context being canceled before the prune operation could complete.

Suggested fix: Ensure that the context is not prematurely canceled or adjust the test to handle the context cancellation appropriately. Consider increasing the timeout or refactoring the code to ensure the prune operation completes within the expected time frame.