Fix flat file import with Entra authentication (#21442)

[kburtram]

Fixes #21442. When using Entra auth, the connection string contains User ID and Authentication properties that conflict with setting AccessToken on SqlConnection. Strip conflicting auth properties from the connection string and refresh the token before sending the import request.

[Copilot]

Pull request overview

Fixes flat file import failures for Microsoft Entra (Azure MFA) connections by ensuring a valid access token is used and by sanitizing the connection string so it’s compatible with setting AccessToken in SqlClient.

Changes:

• Added stripEntraAuthPropertiesFromConnectionString utility to remove auth keywords that conflict with access-token usage.
• Updated flat file import flow to refresh Entra token when needed and send a sanitized connection string to the flat file service.
• Added unit tests covering the new connection-string sanitization helper.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
extensions/mssql/src/controllers/flatFileImportWebviewController.ts	Refreshes Entra token for Azure MFA and sends a sanitized connection string for import.
extensions/mssql/src/flatFile/flatFileUtils.ts	Introduces helper to strip conflicting auth properties from connection strings.
extensions/mssql/test/unit/flatFileUtils.test.ts	Adds unit tests for the new connection-string sanitization behavior.

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[github-actions]

PR Changes

Category	Target Branch	PR Branch	Difference
vscode-mssql VSIX	6402 KB	6403 KB	⚪ 1 KB ( 0% )
sql-database-projects VSIX	7060 KB	7060 KB	⚪ 0 KB ( 0% )
data-workspace VSIX	535 KB	535 KB	⚪ 0 KB ( 0% )

[codecov-commenter]

Codecov Report

❌ Patch coverage is 81.25000% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.54%. Comparing base (e86d4f9) to head (5ec565b).
⚠️ Report is 49 commits behind head on main.

Files with missing lines	Patch %	Lines
...src/controllers/flatFileImportWebviewController.ts	52.63%	9 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #21513   +/-   ##
=======================================
  Coverage   72.53%   72.54%           
=======================================
  Files         330      331    +1     
  Lines       98198    98243   +45     
  Branches     5433     5439    +6     
=======================================
+ Hits        71231    71267   +36     
- Misses      26967    26976    +9     

Files with missing lines	Coverage Δ
extensions/mssql/src/flatFile/flatFileUtils.ts	100.00% <100.00%> (ø)
...src/controllers/flatFileImportWebviewController.ts	91.44% <52.63%> (-1.61%)	⬇️

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[kburtram]

@laurenastrid1 could you please take a look at this PR when you have a moment? Thanks!

[laurenastrid1]

Thanks for fixing this bug!