Fix content-type as application/json for system-schema api

schema-core/src/main/java/org/opengroup/osdu/schema/api/SchemaController.java

@@ -38,7 +38,7 @@ import javax.validation.Valid;
 import static org.opengroup.osdu.schema.constants.SchemaConstants.GET_SCHEMA_200_RESPONSE;
 
 @RestController
-@RequestMapping("schema")
+@RequestMapping(value = "schema", produces = "application/json")
 @Tag(name = "schema-api", description = "Schema API - Core Schema related endpoints")
 public class SchemaController {
 

schema-core/src/main/java/org/opengroup/osdu/schema/api/SystemSchemaController.java

@@ -37,7 +37,7 @@ public class SystemSchemaController {
     @ApiResponses(value = {
             @ApiResponse(responseCode = "200", description = "Schema updated", content = { @Content(schema = @Schema(implementation = SchemaInfo.class)) }),
             @ApiResponse(responseCode = "201", description = "Schema created", content = { @Content(schema = @Schema(implementation = SchemaInfo.class)) }),
-            @ApiResponse(responseCode = "400", description = "Bad user input. Mandatory fields missing or unacceptable value passed to API",  content = {@Content(schema = @Schema(implementation = AppError.class ))}),
+            @ApiResponse(responseCode = "400", description = "Bad user input. Mandatory fields missing or unacceptable value passed to API",  content = {@Content(mediaType = "application/json", schema = @Schema(implementation = AppError.class ))}),
             @ApiResponse(responseCode = "401", description = "Unauthorized",  content = {@Content(schema = @Schema(implementation = AppError.class ))}),
             @ApiResponse(responseCode = "403", description = "User not authorized to perform the action.",  content = {@Content(schema = @Schema(implementation = AppError.class ))}),
             @ApiResponse(responseCode = "404", description = "Not Found",  content = {@Content(schema = @Schema(implementation = AppError.class ))}),