refactor: remove redundant test case and cleanup remaining testcase

Author: DannyvdSluijs

tests/Constraints/AdditionalPropertiesTest.php

@@ -189,40 +189,22 @@ public function getValidTests(): array
                   "additionalProperties": true
                 }'
             ],
-            [
-                '{
-                  "prop1": {
-                    "prop2": "a"
-                  }
-                }',
+            'additional property casted into int when actually is numeric string (#784)' => [
                 '{
-                  "type": "object",
-                  "additionalProperties": {
-                    "type": "object",
-                    "properties": {
-                      "prop2": {
-                        "type": "string"
-                      }
+                    "prop1": {
+                        "123": "a"
                     }
-                  }
-                }'
-            ],
-            [
-                '{
-                  "prop1": {
-                    "123": "a"
-                  }
                 }',
                 '{
-                  "type": "object",
-                  "additionalProperties": {
                     "type": "object",
-                    "properties": {
-                      "123": {
-                        "type": "string"
-                      }
+                    "additionalProperties": {
+                        "type": "object",
+                        "properties": {
+                            "123": {
+                                "type": "string"
+                            }
+                        }
                     }
-                  }
                 }'
             ],
         ];