feat: support ignoring nesting for prefer-conditional-expressions

[incendial]

What is the purpose of this pull request? (put an "X" next to an item)

• Documentation update
• Bug fix
• New rule
• Changes an existing rule
• Add autofixing to a rule
• Add a CLI option
• Add something to the core
• Other, please explain:

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[github-actions]

Dart Code Metrics unused files report of dart_code_metrics. ✅

Summary

• Scanned package folders: bin, example, lib
• No unused files found! ✅

[github-actions]

Dart Code Metrics analyze report of dart_code_metrics. ✅

Summary

• Scanned folders: bin, example, lib, test

• Total scanned files: 548

• Total lines of source code: 9758

• Total classes: 419

• Average Cyclomatic Number per line of code: 0.37 / 2

• Average Source Lines of Code per method: 6

• Total tech debt: 2072.0 hours

• Found issues: 5 ⚠

[codecov]

Codecov Report

Merging #1122 (5b1724e) into master (a352607) will decrease coverage by 0.01%.
The diff coverage is 88.46%.

@@            Coverage Diff             @@
##           master    #1122      +/-   ##
==========================================
- Coverage   85.19%   85.18%   -0.02%     
==========================================
  Files         342      343       +1     
  Lines        7540     7554      +14     
==========================================
+ Hits         6424     6435      +11     
- Misses       1116     1119       +3     

Impacted Files	Coverage Δ
...pressions/prefer_conditional_expressions_rule.dart	93.75% <50.00%> (-6.25%)	⬇️
.../prefer_conditional_expressions/config_parser.dart	100.00% <100.00%> (ø)
...s_list/prefer_conditional_expressions/visitor.dart	100.00% <100.00%> (ø)
.../rules_list/prefer_static_class/config_parser.dart	100.00% <100.00%> (ø)
.../prefer_static_class/prefer_static_class_rule.dart	78.26% <100.00%> (ø)

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more