Fix error detail throwing NPE for cause()

[HindujaB]

Purpose

Describe the problems, issues, or needs driving this feature/fix and include links to related issues.

Fixes #42248

Approach

added a detail type

Samples

Provide high-level details about the samples related to this feature.

Remarks

List any other known issues, related PRs, TODO items, or any other notes related to the PR.

Check List

• Read the Contributing Guide
• Updated Change Log
• Checked Tooling Support (#)
• Added necessary tests
  • Unit Tests
  • Spec Conformance Tests
  • Integration Tests
  • Ballerina By Example Tests
• Increased Test Coverage
• Added necessary documentation
  • API documentation
  • Module documentation in Module.md files
  • Ballerina By Examples

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.70%. Comparing base (559f3b8) to head (3c8ebcd).
Report is 104 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #42249      +/-   ##
============================================
- Coverage     76.71%   76.70%   -0.01%     
- Complexity    53085    53086       +1     
============================================
  Files          2882     2882              
  Lines        200043   200044       +1     
  Branches      26050    26050              
============================================
- Hits         153455   153449       -6     
- Misses        38138    38145       +7     
  Partials       8450     8450              

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[gabilang]

LGTM