Limit txpool size when inserting an Entry

[chenyukang]

What problem does this PR solve?

Problem Summary:

Currently, the limit_size is only invoked by _update_tx_pool_for_reorg, so we only shrink tx_pool size when generating a new block. Ideally, we should also limit size when inserting a new Entry into pool.

What is changed and how it works?

What's Changed:
Invoke limit_size in submit_entry.

Related changes

• PR to update owner/repo:
• Need to cherry-pick to the release branch

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code ci-runs-only: [ quick_checks,linters ]

Side effects

• Performance regression
• Breaking backward compatibility

Release note

Title Only: Include only the PR title in the release note.

[chenyukang]

I ran a benchmark testing for this PR, seems there is no effect on TPS:

duration send tx tps 619,duration avg delay 12.895ms,sum tps:620

cc @gpBlockchain @zhangsoledad