adding a regex pattern for file_hash_t type

Signed-off-by: Rajas Panat <[email protected]>

dictionary.json

@@ -4873,6 +4873,7 @@
         "observable": 8,
         "caption": "Hash",
         "description": "Hash. A unique value that corresponds to the content of the file, image, ja3_hash or hassh found in the schema. For example MD5: <code>3172ac7e2b55cbb81f04a6e65855a628</code>.",
+        "regex": "[a-fA-F0-9]+",
         "type": "string_t",
         "type_name": "String"
       },