chore: remove unnecessary skip_failed_rules config in slt (apache#18117)

## Which issue does this PR close?

<!--
We generally require a GitHub issue to be filed for all bug fixes and
enhancements and this helps us generate change logs for our releases.
You can link an issue to this PR using the GitHub syntax. For example
`Closes #123` indicates that this PR will close issue #123.
-->

- Closes apache#3695
- Closes apache#3797

## Rationale for this change

<!--
Why are you proposing this change? If this is already explained clearly
in the issue then this section is not needed.
Explaining clearly why changes are proposed helps reviewers understand
your changes and offer better suggestions for fixes.
-->

Was looking at above issues and I don't believe we skip the failed rules
for any tests anymore (default for the config is also `false`), apart
from this cleanup, so filing this PR so we can close the issues. Seems
we only do in this `window.slt` test after this fix:


https://github.com/apache/datafusion/blob/621a24978a7a9c6d2b27973d1853dbc8776a56b5/datafusion/sqllogictest/test_files/window.slt#L2587-L2611

Which seems intentional.

## What changes are included in this PR?

<!--
There is no need to duplicate the description in the issue here but it
is sometimes worth providing a summary of the individual changes in this
PR.
-->

Remove unnecessary `skip_failed_rules` config.

## Are these changes tested?

<!--
We typically require tests for all PRs in order to:
1. Prevent the code from being accidentally broken by subsequent changes
2. Serve as another way to document the expected behavior of the code

If tests are not included in your PR, please explain why (for example,
are they covered by existing tests)?
-->

Existing tests.

## Are there any user-facing changes?

<!--
If there are user-facing changes then we may require documentation to be
updated before approving the PR.
-->

No.

<!--
If there are any breaking changes to public APIs, please add the `api
change` label.
-->

Author: Jefffrey

datafusion/sqllogictest/test_files/timestamps.slt

@@ -643,11 +643,7 @@ select date '1994-01-01' - interval '1' day as date;
 ----
 1993-12-31
 
-
 # cast_string_to_time()
-statement ok
-set datafusion.optimizer.skip_failed_rules = false
-
 query DDDD
 select
         time '08:09:10.123456789' as time_nano,
@@ -668,10 +664,6 @@ SELECT TIME '24:01:02' as time;
 query error Arrow error: Parser error: Invalid timezone "ZZ": failed to parse timezone
 SELECT TIMESTAMP '2023-12-05T21:58:10.45ZZ';
 
-statement ok
-set datafusion.optimizer.skip_failed_rules = true
-
-
 # cast_to_timestamp_twice
 query P
 select to_timestamp(a) from (select to_timestamp(1) as a) A;