### What changes were proposed in this pull request?
octet_length: caliculate the byte length of strings
bit_length: caliculate the bit length of strings
Those two string related functions are only implemented on SparkSQL, not on Scala, Python and R.
### Why are the changes needed?
Those functions would be useful for multi-bytes character users, who mainly working with Scala, Python or R.
### Does this PR introduce _any_ user-facing change?
Yes. Users can call octet_length/bit_length APIs on Scala(Dataframe), Python, and R.
### How was this patch tested?
unit tests
Closes#33992 from yoda-mon/add-bit-octet-length.
Authored-by: Leona Yoda <yodal@oss.nttdata.com>
Signed-off-by: Kousuke Saruta <sarutak@oss.nttdata.com>
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