Skip getModule E2E tests on in-box Windows PowerShell

CanSendGetModuleRequestAsync and CanSendGetModuleRequestForMissingModuleAsync
were the only tests in LanguageServerProtocolMessageTests still using
[SkippableFact]/[Fact] instead of [SkippableFactOnWindowsPowerShell]. After the
rebase onto main's E2E harness changes (#2323), LSPTestsFixture no longer starts
the server under in-box Windows PowerShell, so PsesLanguageClient is null on that
leg. Every other test in the class skips at discovery time there; these two ran
anyway and threw NullReferenceException. Decorate them with the same attribute so
they skip at discovery alongside their siblings. The attribute keeps the
SkippableFact discoverer, so the Constrained Language Mode Skip.If in
CanSendGetModuleRequestAsync still works, and both tests continue to run on
Linux, macOS, and the PowerShell 7 Windows legs.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: andyleejordan

test/PowerShellEditorServices.Test.E2E/LanguageServerProtocolMessageTests.cs

@@ -1306,7 +1306,7 @@ await PsesLanguageClient
             Assert.Equal("Get-ChildItem | Where-Object Name | ForEach-Object Name", expandAliasResult.Text);
         }
 
-        [SkippableFact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task CanSendGetModuleRequestAsync()
         {
             Skip.If(PsesStdioLanguageServerProcessHost.RunningInConstrainedLanguageMode,
@@ -1344,7 +1344,7 @@ await PsesLanguageClient
             Assert.Equal(module.Version, pinned.Version);
         }
 
-        [Fact]
+        [SkippableFactOnWindowsPowerShell]
         public async Task CanSendGetModuleRequestForMissingModuleAsync()
         {
             PSModuleMessage module =