Getting a request has failed and cannot read properties of undefined scheme instead of error highlighting

Environment (please complete the following information):

• OS Windows 10
• Extension version (e.g., 1.2.3): 2.1.0

Describe the bug:
Getting a message that a request has failed and that a scheme can't be found when opening an HTML document

Repro steps:

• Open an HTML document, get the error

Expected behavior:

Seeing issues flagged up in the HTML document

Additional context:

Output of the debugger (this is only shown a second so you need to be quick to copy and paste)

[Error - 21:04:04] Server initialization failed.
TypeError: Cannot read properties of undefined (reading 'scheme')
    at Ue (c:\Users\chheilma\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\api\node\extensionHostProcess.js:106:30596)
    at Array.forEach (<anonymous>)
    at Ue (c:\Users\chheilma\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\api\node\extensionHostProcess.js:106:30524)
    at Object.registerCodeActionsProvider (c:\Users\chheilma\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\api\node\extensionHostProcess.js:106:35801)
    at CodeActionFeature.registerLanguageProvider (c:\Users\chheilma\.vscode\extensions\ms-edgedevtools.vscode-edge-devtools-2.1.0\out\extension.js:70153:36)
    at CodeActionFeature.register (c:\Users\chheilma\.vscode\extensions\ms-edgedevtools.vscode-edge-devtools-2.1.0\out\extension.js:69624:33)
    at CodeActionFeature.initialize (c:\Users\chheilma\.vscode\extensions\ms-edgedevtools.vscode-edge-devtools-2.1.0\out\extension.js:70103:14)
    at LanguageClient.initializeFeatures (c:\Users\chheilma\.vscode\extensions\ms-edgedevtools.vscode-edge-devtools-2.1.0\out\extension.js:71487:21)
    at c:\Users\chheilma\.vscode\extensions\ms-edgedevtools.vscode-edge-devtools-2.1.0\out\extension.js:71157:18
[Error - 21:04:04] Starting client failed
TypeError: Cannot read properties of undefined (reading 'scheme')
    at Ue (c:\Users\chheilma\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\api\node\extensionHostProcess.js:106:30596)
    at Array.forEach (<anonymous>)
    at Ue (c:\Users\chheilma\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\api\node\extensionHostProcess.js:106:30524)
    at Object.registerCodeActionsProvider (c:\Users\chheilma\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\api\node\extensionHostProcess.js:106:35801)
    at CodeActionFeature.registerLanguageProvider (c:\Users\chheilma\.vscode\extensions\ms-edgedevtools.vscode-edge-devtools-2.1.0\out\extension.js:70153:36)
    at CodeActionFeature.register (c:\Users\chheilma\.vscode\extensions\ms-edgedevtools.vscode-edge-devtools-2.1.0\out\extension.js:69624:33)
    at CodeActionFeature.initialize (c:\Users\chheilma\.vscode\extensions\ms-edgedevtools.vscode-edge-devtools-2.1.0\out\extension.js:70103:14)
    at LanguageClient.initializeFeatures (c:\Users\chheilma\.vscode\extensions\ms-edgedevtools.vscode-edge-devtools-2.1.0\out\extension.js:71487:21)
    at c:\Users\chheilma\.vscode\extensions\ms-edgedevtools.vscode-edge-devtools-2.1.0\out\extension.js:71157:18
Error loading "hint" package from "c:\codes\web-cheatcodes\web-cheatcodes"
Trying to load shared version
Found hint at c:\Users\chheilma\AppData\Roaming\Code\User\globalStorage\ms-edgedevtools.vscode-edge-devtools\node_modules\hint\dist\src\lib\index.js

Reproduce this with extension version 2.1.0 by opening an HTML document and inspect the server initialization output. Start at CodeActionFeature.registerLanguageProvider in the extension stack shown in the report, then trace the language-provider registration that triggers the undefined scheme error. Done means the client starts successfully and issues are highlighted in the HTML document.