fix($login-and-register): input border breaks when focus and with validation class (#2026)

build/scss/_login_and_register.scss

@@ -38,10 +38,40 @@
   .input-group {
     .form-control {
       border-right: none;
+
+      &:focus {
+        box-shadow: none;
+        & ~ .input-group-append .input-group-text {
+          border-color: $input-focus-border-color;
+        }
+      }
+      
+      &.is-valid {
+        &:focus {
+          box-shadow: none;
+        }
+        & ~ .input-group-append .input-group-text {
+          border-color: $success;
+        }
+      }
+
+      &.is-invalid {
+        &:focus {
+          box-shadow: none;
+        }
+        & ~ .input-group-append .input-group-text {
+          border-color: $danger;
+        }
+      }
     }
     .input-group-text {
       color: #777;
       background-color: transparent;
+      border-left: none;
+      transition: $input-transition;
+      // Fix boostrap issue temporarily https://github.com/twbs/bootstrap/issues/25110
+      border-bottom-right-radius: $border-radius !important;
+      border-top-right-radius: $border-radius !important;
     }
   }
 }