Enable AAD signing key issuer validation for API Key auth

[schmittjoseph]

Summary

When using API Key auth, enable AAD signing key issuer validation -- this is required by CodeQL.

We already have an official way of performing AAD auth, so this is change largely a no-op. The full effects of adding this validation are as follows:

• If an OpenIdConnectConfiguration is configured then extra validation will be performed on it. When using API Key auth, we never add this configuration so nothing will happen unless the user somehow has.
• If the API key is derived from an X.509 certificate then we will now validate the lifetime of the certificate (if it is already active and non-expired).

Release Notes Entry

[schmittjoseph]

/backport to release/8.0

[schmittjoseph]

/backport to release/7.x

[github-actions]

Started backporting to release/8.0: https://github.com/dotnet/dotnet-monitor/actions/runs/8744153570

[schmittjoseph]

/backport to release/6.x

[github-actions]

Started backporting to release/7.x: https://github.com/dotnet/dotnet-monitor/actions/runs/8744154827

[github-actions]

Started backporting to release/6.x: https://github.com/dotnet/dotnet-monitor/actions/runs/8744156068

[github-actions]

@schmittjoseph backporting to release/6.x failed, the patch most likely resulted in conflicts.

Please backport manually using one of the below commands, followed by git am --continue once the merge conflict has been resolved.

PowerShell

(Invoke-WebRequest "https://github.com/dotnet/dotnet-monitor/commit/b3e64938549c60d95ebf6dad945de4aaee563ff0.patch").Content | git am --3way --ignore-whitespace --exclude="documentation/**.md" --keep-non-patch

Bash

curl -sSL "https://github.com/dotnet/dotnet-monitor/commit/b3e64938549c60d95ebf6dad945de4aaee563ff0.patch" | git am --3way --ignore-whitespace --exclude="documentation/**.md" --keep-non-patch

---

git am error output:

$ git am --3way --ignore-whitespace --exclude="documentation/**.md" --keep-non-patch changes.patch

Applying: Enable EnableAadSigningKeyIssuerValidation (#6459)
.git/rebase-apply/patch:22: trailing whitespace.
            // Required for CodeQL. 
.git/rebase-apply/patch:45: trailing whitespace.
            // Required for CodeQL. 
warning: 2 lines add whitespace errors.
Using index info to reconstruct a base tree...
A	src/Tools/dotnet-monitor/Auth/ApiKey/JwtBearerOptionsExtensions.cs
Falling back to patching base and 3-way merge...
Auto-merging src/Tools/dotnet-monitor/Auth/JwtBearerPostConfigure.cs
CONFLICT (content): Merge conflict in src/Tools/dotnet-monitor/Auth/JwtBearerPostConfigure.cs
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0001 Enable EnableAadSigningKeyIssuerValidation (#6459)
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Error: The process '/usr/bin/git' failed with exit code 128