chore: move css properties to proper file

Author: isekovanic

src/v2/styles/MessageInput/MessageInput-layout.scss

@@ -130,12 +130,9 @@
   }
 
   .str-chat__stop-generating-button {
-    background-image: var(--str-chat__circle-stop-icon);
     width: calc(var(--str-chat__spacing-px) * 30);
     height: calc(var(--str-chat__spacing-px) * 28);
     cursor: pointer;
-    background-color: transparent;
-    border-width: 0;
   }
 
   .str-chat__send-button {

src/v2/styles/MessageInput/MessageInput-theme.scss

@@ -168,10 +168,10 @@
 
   /* Box shadow applied to the cooldown timer */
   --str-chat__cooldown-box-shadow: none;
-  
+
   /* Color applied to an icon in a button that opens attachment selector */
   --str-chat__attachment-selector-button-icon-color: var(--str-chat__text-low-emphasis-color);
-  
+
   /* Color applied to an icon in a button that opens attachment selector when hovered over */
   --str-chat__attachment-selector-button-icon-color-hover: var(--str-chat__primary-color);
 
@@ -221,6 +221,12 @@
     }
   }
 
+  .str-chat__stop-generating-button {
+    background-image: var(--str-chat__circle-stop-icon);
+    background-color: transparent;
+    border-width: 0;
+  }
+
   .str-chat__send-button {
     --str-chat-icon-color: var(--str-chat__message-send-color);
     @include utils.component-layer-overrides('message-send');
@@ -342,4 +348,4 @@
       mask: var(--str-chat__poll-icon) no-repeat center / contain;
     }
   }
-}
+}