Analyzer: Fix HTMLAttributes mode defaults

[peterthorpe81]

Fixes a bug that prevented the analyzers HTMLAttributes mode from using a default list of HTML attributes.

Description

The new HTMLAttributes mode of the analyzer isn't using the default list of HTML attributes when the .csproj doesn't contain an alternative list. This is because MudAllowedAttributeList is string.Empty rather than null. This wasn't apparent in testing because I have to manually create the configuration.

How Has This Been Tested?

Updated test code to make the value string.Empty rather than null and tested.

Type of Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation (fix or improvement to the website or code docs)

Checklist

• The PR is submitted to the correct branch (dev).
• My code follows the code style of this project.
• I've added relevant tests.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud