Fix deserialization failure in Change Metadata (#2382)

* Fix deserialization failure from String to Map

Fix deserialization failure from String to Map that caused the following exception:
Resolved [org.springframework.web.bind.MethodArgumentNotValidException: Validation failed for argument [0] in public org.springframework.http.ResponseEntity<byte[]> stirling.software.SPDF.controller.api.misc.MetadataController.metadata(stirling.software.SPDF.model.api.misc.MetadataRequest) throws java.io.IOException: [Field error in object 'metadataRequest' on field 'allRequestParams': rejected value [{"customKey1" : "YourCustomKey", "customKeyValue1", "YourCustomValue"}]; codes [typeMismatch.metadataRequest.allRequestParams,typeMismatch.allRequestParams,typeMismatch.java.util.Map,typeMismatch];

* Fix form binding for dynamic Map entries in Change Metadata

- Implemented support for dynamic key-value inputs in Change Metadata form using proper `name` attributes for Map (`allRequestParams`) binding.
- Fix form binding for dynamic Map (`allRequestParams`) entries in Change Metadata as the `allRequestParams` (Map name) was being sent as an empty map.

src/main/resources/templates/misc/change-metadata.html

@@ -164,13 +164,13 @@
                     keyInput.type = "text";
                     keyInput.placeholder = 'Key';
                     keyInput.className = "form-control";
-                    keyInput.name = "customKey" + count;
+                    keyInput.name = `allRequestParams[customKey${count}]`;
 
                     const valueInput = document.createElement("input");
                     valueInput.type = "text";
                     valueInput.placeholder = 'Value';
                     valueInput.className = "form-control";
-                    valueInput.name = "customValue" + count;
+                    valueInput.name = `allRequestParams[customValue${count}]`;
                     count = count + 1;
 
                     const formGroup = document.createElement("div");