Fix incorrect condition for error filtering

Fixes: godotengine#87643

The original condition stopped immediately after checking for 'searchText' in the 'Message' field, resulting in premature termination of subsequent checks. This fix ensures that all relevant conditions are appropriately evaluated before determining the filtering outcome.

Additionally, accompanying changes include improved code readability for better comprehension. This adjustment enhances the maintainability of the error filtering mechanism, contributing to a more robust codebase overall.

(cherry picked from commit d81c9c3)

modules/mono/editor/GodotTools/GodotTools/Build/BuildProblemsView.cs

@@ -308,14 +308,14 @@ private bool ShouldDisplayDiagnostic(BuildDiagnostic diagnostic)
                 return false;
 
             string searchText = _searchBox.Text;
-            if (!string.IsNullOrEmpty(searchText) &&
-                (!diagnostic.Message.Contains(searchText, StringComparison.OrdinalIgnoreCase) ||
-                !(diagnostic.File?.Contains(searchText, StringComparison.OrdinalIgnoreCase) ?? false)))
-            {
-                return false;
-            }
-
-            return true;
+            if (string.IsNullOrEmpty(searchText))
+                return true;
+            if (diagnostic.Message.Contains(searchText, StringComparison.OrdinalIgnoreCase))
+                return true;
+            if (diagnostic.File?.Contains(searchText, StringComparison.OrdinalIgnoreCase) ?? false)
+                return true;
+
+            return false;
         }
 
         private Color? GetProblemItemColor(BuildDiagnostic diagnostic)