Allow backtick around fields in sort cmd

[joshuali925]

Description

currently this doesn't work

❯ curl -X POST -k -H 'Content-Type: application/json' localhost:9200/_plugins/_ppl -d '{"query":"source=accounts | sort `age`"}'
{
  "error": {
    "reason": "Invalid Query",
    "details": "can't resolve Symbol(namespace=FIELD_NAME, name=`age`) in type env",
    "type": "SemanticCheckException"
  },
  "status": 400
}%

The PR will add support for fields in backticks so sort behavior is consistent with other commands.
This PR also fixes some build issues

Issues Resolved

[List any issues this PR will resolve]

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov]

Codecov Report

Merging #1688 (2978737) into main (57ce303) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##               main    #1688   +/-   ##
=========================================
  Coverage     97.27%   97.27%           
  Complexity     4330     4330           
=========================================
  Files           388      388           
  Lines         10807    10807           
  Branches        761      761           
=========================================
  Hits          10513    10513           
  Misses          287      287           
  Partials          7        7           

Flag	Coverage Δ
sql-engine	97.27% <100.00%> (ø)

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Impacted Files	Coverage Δ
...pensearch/sql/ppl/parser/AstExpressionBuilder.java	100.00% <100.00%> (ø)

[dai-chen]

Thanks for the fix!