fix: render error messages for invalid templates (#3088)

Currently direct templates can be created without the required
signatures fields for signers.

This means that the document can be fully signed by everyone but will
ultimately fail the sealing step which leaves the document in an
unrecoverable state.

apps/remix/app/utils/toast-error-messages.ts

@@ -32,6 +32,10 @@ export const getDirectTemplateErrorMessage = (code: string): ToastMessageDescrip
   return match(code)
     .with('RECIPIENT_LIMIT_EXCEEDED', () => RECIPIENT_LIMIT_EXCEEDED_ERROR_MESSAGE)
     .with(AppErrorCode.TOO_MANY_REQUESTS, () => FAIR_USE_LIMIT_EXCEEDED_ERROR_MESSAGE)
+    .with(AppErrorCode.MISSING_SIGNATURE_FIELD, () => ({
+      title: msg`Missing signature fields`,
+      description: msg`This direct link template cannot be used because one or more signers do not have a signature field assigned.`,
+    }))
     .otherwise(() => ({
       title: msg`Something went wrong`,
       description: msg`We were unable to submit this document at this time. Please try again later.`,
@@ -77,6 +81,10 @@ export const getTemplateUseErrorMessage = (code: string): ToastMessageDescriptor
       title: msg`Error`,
       description: msg`The document was created but could not be sent to recipients.`,
     }))
+    .with(AppErrorCode.MISSING_SIGNATURE_FIELD, () => ({
+      title: msg`Missing signature fields`,
+      description: msg`The document could not be sent because some signers do not have a signature field. Please edit the template and add a signature field for each signer.`,
+    }))
     .with(AppErrorCode.INVALID_BODY, AppErrorCode.INVALID_REQUEST, () => ({
       title: msg`Error`,
       description: msg`The document could not be created because of missing or invalid information. Please review the template's recipients and fields.`,