Fix collation conflict in getIndexInfo() UNION ALL with different server/database collations

[Ananya Garg (Ananya2)]

Summary

Fixes GitHub Issue #2856 - collation conflicts in SQLServerDatabaseMetaData.getIndexInfo() when SQL Server instance and database have different collations.

Problem

The INDEX_INFO_COMBINED_QUERY performs UNION ALL operations between sp_statistics results and sys.indexes metadata. When the SQL Server instance collation differs from the database collation, this causes collation conflict errors in the ORDER BY clause:
Cannot resolve collation conflict between "SQL_Latin1_General_CP1_CI_AS" and "Finnish_Swedish_CI_AS" in UNION ALL operator occurring in ORDER BY statement column 3.

Root Cause

The UNION ALL combines: sp_statistics results (using server/system collation context) and sys.indexes query results (using database collation context).
When ORDER BY processes column 3 (TABLE_NAME), SQL Server cannot resolve the collation difference between the two result sets.

Solution

Added COLLATE DATABASE_DEFAULT to all string columns (NVARCHAR/VARCHAR) in INDEX_INFO_COMBINED_QUERY to prevent collation conflicts when SQL Server instance and database have different collations. 
This fixes UNION ALL ORDER BY failures in mixed collation environments while maintaining comprehensive index coverage.

Closes #2856

[codecov]

Codecov Report

❌ Patch coverage is 71.42857% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 56.46%. Comparing base (303aeb9) to head (c31a6cf).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...soft/sqlserver/jdbc/SQLServerDatabaseMetaData.java	71.42%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2867      +/-   ##
============================================
+ Coverage     56.44%   56.46%   +0.01%     
- Complexity     4559     4569      +10     
============================================
  Files           151      151              
  Lines         34560    34564       +4     
  Branches       5768     5769       +1     
============================================
+ Hits          19508    19517       +9     
- Misses        12418    12427       +9     
+ Partials       2634     2620      -14     

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[Ananya Garg (Ananya2)]

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