Investigate PostgresIntegration for Memory issues

[AbhiPrasad]

We've gotten two different reports (#11897, https://discord.com/channels/621778831602221064/1242436171737333810) that using the postgres integration with Sentry is causing memory issues.

Let's investigate this further.

[timfish]

I conducted some testing of the pg instrumentation in isolation with Postgres 13.14 with many thousands of transactions per second and both CPU and memory seem roughly similar and there were no timeouts.

The only changes to the otel instrumentation over the last year have been a couple of small PRs to reduce allocations.

[AbhiPrasad]

Maybe these OTEL upstream changes have helped. Let's close this for now then and also close #11897. We can create another issue if we get another reproduction. Thanks for taking a look @timfish!