[SPARK-59063][SQL] Use byte-length guard in LikeSimplification

[marcuslin123]

What changes were proposed in this pull request?

This PR changes the prefix%suffix branch of LikeSimplification to use
OctetLength with the UTF-8 byte lengths of the prefix and suffix. It also
updates the optimizer plan tests and adds SPARK-59063 coverage for multibyte
UTF-8 characters.

Why are the changes needed?

Length scans every input string to count code points. OctetLength reads the
stored UTF-8 byte length in constant time, while the existing StartsWith and
EndsWith predicates continue to enforce the pattern boundaries.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

build/sbt catalyst/scalastyle catalyst/Test/scalastyle \
  'catalyst/testOnly org.apache.spark.sql.catalyst.optimizer.LikeSimplificationSuite'

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

Generated-by: Codex (GPT-5) for code assistance.