Bumped Verify.Xunit to version 26.6.0

[jamescrosswell]

#skip-changelog

Summary

The only changes in this PR are bumping the version of Verify.Xunit from version 22.11.4 to version 26.6.0 and removing all the [UsesVerify] attributes that are no longer required or supported by the new version of Verify.

Important Note

This change results in a missing a debug image in test/Sentry.NLog.Tests/IntegrationTests.Simple.Mono4_0.verified.txt.

Oddly the debug image is only missing in CI. When I run this test on my Mac locally, it passes.

For the time being, we'll skip this test on Mono in CI. This issue has been created instead:

• Missing DebugImage running on Mono in CI #3823

Here's the diff on CI when running this test on macos-15 (arm64) and ubuntu (x64)

              SentryExceptions: [
                {
                  Type: System.Exception,
                  Value: Exception message,
                  Stacktrace: {
                    Frames: [
                      {
                        FileName: ,
                        Function: Task IntegrationTests.Simple(),
                        Module: null,
                        LineNumber: null,
                        ColumnNumber: null,
                        AbsolutePath: null,
                        ContextLine: null,
                        InApp: false,
                        Package: Sentry.NLog.Tests, Version=SCRUBBED, Culture=SCRUBBED, PublicKeyToken=SCRUBBED,
                        Platform: null,
                        ImageAddress: null,
                        SymbolAddress: null,
                        InstructionAddress: 2,
-                       AddressMode: rel:0,
-                       FunctionId: 1
+                       AddressMode: null,
+                       FunctionId: null
                      }
                    ]
                  },
                  Mechanism: {
                    Type: generic,
                    Handled: true,
                    Synthetic: false,
                    IsExceptionGroup: false
-                 }
                  }
-             ],
-             DebugImages: [
-               {
-                 Type: pe_dotnet,
-                 ImageAddress: null,
-                 ImageSize: null,
-                 DebugId: ________-____-____-____-____________-________,
-                 DebugChecksum: ______:________________________________________________________________,
-                 DebugFile: .../Sentry.NLog.Tests.pdb,
-                 CodeId: ______________,
-                 CodeFile: .../Sentry.NLog.Tests.dll
                }
              ],