fix: increase search query max length from 20 to 50 characters

Allows searching by bulk message IDs (e.g. bulk-8dcc3d68-57bd-4913-a5ff-52c107ffc0c9)
which are 41 characters long.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: AchoArnold

api/pkg/validators/message_handler_validator.go

@@ -328,7 +328,7 @@ func (validator MessageHandlerValidator) ValidateMessageSearch(ctx context.Conte
 				"min:0",
 			},
 			"query": []string{
-				"max:20",
+				"max:50",
 			},
 			"token": []string{
 				"required",

web/pages/bulk-messages/index.vue

@@ -102,7 +102,7 @@
             <p class="text--secondary">
               Your 10 most recent bulk SMS uploads are shown below, including a
               delivery status breakdown for each batch. Click
-              <code>View</code> to see individual messages.
+              <code>View</code> to see individual messages on the search page
             </p>
             <v-progress-linear
               v-if="loadingHistory"