[SPARK-52841][SQL][TESTS] Fix PlanStabilitySuite id normalization

### What changes were proposed in this pull request?

This PR fixes and id normalization in `PlanStabilitySuite`s and

### Why are the changes needed?
Currently if we run a subset of `PlanStabilitySuite`s then it might fail due to plan and expression id conflixts:
```
build/sbt "sql/testOnly *TPCDSV1_4_PlanStabilitySuite"
...
[info] - check simplified (tpcds-v1.4/q9) *** FAILED *** (81 milliseconds)
```
This is because the expr id regex doesn't skip and plan id regex doesn't take into account that the plan id is formatted as `id=#...` in `SubqueryExec` nodes.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Existing UTs + manual subset run.

### Was this patch authored or co-authored using generative AI tooling?

No.

Closes #51534 from peter-toth/SPARK-52841-fix-planstability-id-normalization.

Authored-by: Peter Toth <[email protected]>
Signed-off-by: Dongjoon Hyun <[email protected]>

Author: peter-toth