Avoid recording SQL arguments via tracing::instrument

[WaterWhisperer]

PR Info

• Closes [tracing-spans] Add option to remove params from traces #2941

• Dependencies:
  • Add option to remove params from traces #3045

New Features

• None.

Changes

• Skip raw stmt / sql arguments in #[instrument] generated spans across database execution paths.
• Keep record_stmt_in_spans responsible only for manual db.statement recording.

[WaterWhisperer]

record_stmt_in_spans in #3045 already separately controls manual db.statement recording. The remaining leakage here comes from #[instrument] automatically recording function arguments like stmt / sql into spans.

I did not turn that into another runtime option, because this part is driven by the #[instrument] macro itself. Making it configurable would likely require replacing these macro-generated spans with a different manual tracing path.