Flips behavior, validate by default, opt out with Lenient

[brendankowitz]

Description

Take 2 on #4718. This allows the client to specify "Lenient" to opt out of validation...

This pull request includes several changes to improve the handling of search parameter validation in the FHIR server, particularly focusing on the differentiation between strict and lenient handling modes.

Enhancements to Handling Modes:

• src/Microsoft.Health.Fhir.Core/Extensions/PreferHeaderExtensions.cs: Refactored the GetIsStrictHandlingEnabled method to return a boolean directly based on the GetHandlingHeader method, which now checks for SearchParameterHandling.Strict. [1] [2]
• src/Microsoft.Health.Fhir.Core/Features/Operations/Export/CreateExportRequestHandler.cs: Updated the ValidateTypeFilters method to log and skip validation when SearchParameterHandling.Lenient is specified.

Test Adjustments:

• test/Microsoft.Health.Fhir.Shared.Tests.Integration/Features/Operations/Export/CreateExportRequestHandlerTests.cs: Modified test cases to reflect the changes in handling modes, including renaming test methods to specify lenient handling and removing hardcoded strict handling headers. [1] [2] [3] [4]

Related issues

Addresses AB#130227

Testing

Unit tests.

FHIR Team Checklist

• Update the title of the PR to be succinct and less than 65 characters
• Add a milestone to the PR for the sprint that it is merged (i.e. add S47)
• Tag the PR with the type of update: Bug, Build, Dependencies, Enhancement, New-Feature or Documentation
• Tag the PR with Open source, Azure API for FHIR (CosmosDB or common code) or Azure Healthcare APIs (SQL or common code) to specify where this change is intended to be released.
• Tag the PR with Schema Version backward compatible or Schema Version backward incompatible or Schema Version unchanged if this adds or updates Sql script which is/is not backward compatible with the code.
• CI is green before merge
• Review squash-merge requirements

Semver Change (docs)

Patch|Skip|Feature|Breaking (reason)