Issue:3287341 - Drupal 10 Compatiblity support.

fix form class error , limit add to one entity type

Closes #3287341

css/referenced-entity-modal.css

+.register-new-school {
+  display: block;
+  padding: 8px 16px;
+  width: 100%;
+  text-align: center;
+  border-radius: 8px;
+  border: solid 1px #089cdc;
+  font-size: 1.4rem;
+  font-weight: 700;
+  color: #089cdc;
+  margin: 20px auto 0px;
+  background-color: transparent;
+  border: solid 1px #089cdc;
+}
+.register-new-school > * {
+  display: none;
+}
+.register-new-school:hover,.register-new-school:active,.register-new-school:visited,.register-new-school:link,.register-new-school:focus {
+  text-decoration: none;
+  background-color: transparent;
+  color: #089CDC;
+}
+.register-new-school.disabled {
+  pointer-events: none;
+  border: 0;
+  color: #707070;
+}
+.referenced-entity-modal-container {
+  position: relative;
+}
+.referenced-entity-modal-container .field-modal-reset {
+  position: absolute;
+  top: 42px;
+  right: 50px;
+  font-size: 2.5rem;
+  z-index: 9;
+}
+.referenced-entity-modal-container .field-modal-reset:hover {
+  cursor: pointer;
+}
+.referenced-entity-modal-container .form-type-entity-autocomplete .input-group {
+  border: 1px solid #B7B7B7;
+  border-radius: 5px;
+  border-right: none;
+}
+.referenced-entity-modal-container .form-type-entity-autocomplete .input-group input {
+  border: none;
+}
+.referenced-entity-modal-container .form-type-entity-autocomplete .input-group input:focus {
+  box-shadow: none;
+} 
+.referenced-entity-modal-container.value-set .referenced-entity-modal-input {
+  overflow: hidden; 
+  text-overflow: ellipsis;
+  width: 100%;
+}
+.referenced-entity-modal-container .field-modal-reset {
+  display: none;
+}
+.referenced-entity-modal-container.value-set .field-modal-reset{
+  display: block;
+}
+@media screen and (max-width: 767px) {
+  .referenced-entity-modal-container.value-set .referenced-entity-modal-input {
+    width: 100%;
+  }
+} 
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