feat: Support Regex validation for custom attributes (#7856)

This allows a user to add/update a custom regex and a cue while defining custom attributes(Only applicable for type- text).
While adding/editing custom attributes, the values are validated against the attribute definition regex, and if it is incorrect, a cue message or default error message is shown and restricts invalid values from being saved.

Fixes: #6866

db/schema.rb

@@ -501,6 +501,8 @@ ActiveRecord::Schema[7.0].define(version: 2023_12_19_073832) do
     t.datetime "updated_at", null: false
     t.text "attribute_description"
     t.jsonb "attribute_values", default: []
+    t.string "regex_pattern"
+    t.string "regex_cue"
     t.index ["account_id"], name: "index_custom_attribute_definitions_on_account_id"
     t.index ["attribute_key", "attribute_model", "account_id"], name: "attribute_key_model_index", unique: true
   end