Update project configuration and snapshot files

- Changed the default project file from `plugin.project.json` to `plugin.project.json5` in `build.rs`.
- Added new project configuration files in JSON5 format for various test cases, including `default.project.json5`, `client_in_folder`, `csv_bug_145`, and others.
- Updated snapshot files to reflect changes in instance structure and properties, ensuring consistency with the new project configurations.
- Removed unnecessary script and module instances from snapshot files to streamline the testing process.

rojo-test/syncback-tests/duplicate_rojo_id/input-project/default.project.json5

@@ -4,7 +4,7 @@
     "$className": "DataModel",
     "ReplicatedStorage": {
       "container": {
-        "$path": "container.model.json"
+        "$path": "container.model.json5"
       }
     }
   }

rojo-test/syncback-tests/nested_projects/expected/default.project.json5

@@ -4,7 +4,7 @@
     "$className": "DataModel",
     "ReplicatedStorage": {
       "Nested": {
-        "$path": "nested.project.json"
+        "$path": "nested.project.json5"
       }
     }
   }

rojo-test/syncback-tests/nested_projects/input-project/default.project.json5

@@ -4,7 +4,7 @@
     "$className": "DataModel",
     "ReplicatedStorage": {
       "Nested": {
-        "$path": "nested.project.json"
+        "$path": "nested.project.json5"
       }
     }
   }

rojo-test/syncback-tests/nested_projects_weird/input-project/default.project.json5

@@ -4,12 +4,12 @@
     "$className": "DataModel",
     "ReplicatedStorage": {
       "modules": {
-        "$path": "client-only.project.json"
+        "$path": "client-only.project.json5"
       }
     },
     "ServerStorage": {
       "modules": {
-        "$path": "server-only.project.json"
+        "$path": "server-only.project.json5"
       }
     }
   }

rojo-test/syncback-tests/project_reserialize/expected/default.project.json5

@@ -10,7 +10,7 @@
         "$path": "attribute_mismatch.luau"
       },
       "property_mismatch": {
-        "$path": "property_mismatch.project.json"
+        "$path": "property_mismatch.project.json5"
       },
       "$properties": {
         "EditorLiveScripting": {

rojo-test/syncback-tests/project_reserialize/input-project/default.project.json5

@@ -9,7 +9,7 @@
       "$path": "attribute_mismatch.luau"
     },
     "property_mismatch": {
-      "$path": "property_mismatch.project.json"
+      "$path": "property_mismatch.project.json5"
     }
   }
 }