[tests] Fix generation of random ids for projects

[radical]

In Aspire.Workload.Tests, Path.GetRandomFile() is used to generate part of the project id, like jdzjmany.try, and that is used to generate the namespace names like starter_test.Debug-nunit_jdzjmany.try.Web. But this generated namespace name invalid because of the .try.

The fix is to sanitize the string returned from Path.GetRandomFile() for use as an identifier.

The failures shows up as a build error:

C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\Program.cs(1,41): error CS1001: Identifier expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\Program.cs(1,41): error CS1002: ; expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\Program.cs(1,44): error CS1514: { expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\Program.cs(1,44): error CS1513: } expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\Program.cs(2,41): error CS1001: Identifier expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\Program.cs(2,41): error CS1002: ; expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\Program.cs(2,44): error CS1514: { expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\Program.cs(2,44): error CS1513: } expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\Program.cs(43,11): error CS1513: } expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\WeatherApiClient.cs(1,45): error CS1001: Identifier expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\WeatherApiClient.cs(1,49): error CS0116: A namespace cannot directly contain members such as fields, methods or statements
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\WeatherApiClient.cs(1,45): error CS1514: { expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\WeatherApiClient.cs(1,48): error CS1022: Type or namespace definition, or end-of-file expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\WeatherApiClient.cs(1,52): error CS1022: Type or namespace definition, or end-of-file expected
C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.Web\WeatherApiClient.cs(29,2): error CS1513: } expected
  starter test.Debug-nunit_jdzjmany.try.ApiService -> C:\h\w\ABEA0983\t\testroot\starter test.Debug-nunit_jdzjmany.try\starter test.Debug-nunit_jdzjmany.try.ApiService\bin\Debug\net9.0\starter test.Debug-nunit_jdzjmany.try.ApiService.dll

Similar issue was seen in dotnet/runtime - https://github.com/dotnet/runtime/commit/26990158d9725aa55d0af81f050a7a8e90c35f58