Require individual languages opt-in to Hot Reload

[tmeschter]

Right now the SDK adds the "SupportsHotReload" project capability to every project targeting .NET 6.0 or above:

sdk/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.targets

Lines 1129 to 1132 in e10860e

	<!-- Enable hot reload in 6.0 and newer apps by default -->
	<ItemGroup Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp' AND $([MSBuild]::VersionGreaterThanOrEquals($(TargetFrameworkVersion), '6.0'))">
	<ProjectCapability Include="SupportsHotReload" />
	</ItemGroup>

This puts the burden on languages that do not currently support Hot Reload to know they need to opt out. It would be better to let each individual language opt-in to Hot Reload by adding this project capability in their individual .targets.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[DamianEdwards]

@pranavkm