Fix case insensitive and escaped query on wildcard

[HUSTERGS]

Description

1. fix case insensitve regexp query on wildcard field
2. fix queries contains characters need to be escaped on wildcard field
3. fix null pointer exception cause by plain text regex query on wildcard field
4. add corresponding yml test

As for the comment by @msfroh , It may needs more thorough thinking, so this pr just functionally fixed the problem, the refactoring may leave for the future

Related Issues

Resolves #16754 #16755

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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[github-actions]

✅ Gradle check result for b7629b5: SUCCESS

[codecov]

Codecov Report

Attention: Patch coverage is 71.42857% with 16 lines in your changes missing coverage. Please review.

Project coverage is 72.07%. Comparing base (5ba909a) to head (b7629b5).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...g/opensearch/index/mapper/WildcardFieldMapper.java	71.42%	10 Missing and 6 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #16827      +/-   ##
============================================
- Coverage     72.11%   72.07%   -0.04%     
+ Complexity    65237    65184      -53     
============================================
  Files          5318     5318              
  Lines        304003   304041      +38     
  Branches      43992    43998       +6     
============================================
- Hits         219228   219149      -79     
- Misses        66874    66955      +81     
- Partials      17901    17937      +36     

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