Refactor configurations footer landscape placeholder styles and remove unused api call cancellation handler

- use 'is landscape' in `packages/ui/src/components/editor/prompt/Configurations/Configurations.tsx` and use it for [Fragment]
- use css mixin instad of [Fragment]

├── apps
│   └── editor
│       └── src
│           └── views
│               └── prompt
│                   └── frontend
│                       ├── Home
│                       │   ├── Home.module.scss
│                       │   └── Home.tsx
│                       ├── Main
│                       │   └── MainView
│                       │       ├── MainView.module.scss
│                       │       ├── MainView.tsx
│                       │       └── components
│                       │           └── Header
│                       │               ├── Header.module.scss
│                       │               └── Header.tsx
│                       └── hooks
│                           └── use-is-landscape.ts
└── packages
    └── ui
        └── src
            └── components
                └── editor
                    └── prompt
                        └── Configurations
                            ├── Configurations.module.scss
                            └── Configurations.tsx

Author: robertpiosik

apps/editor/src/views/prompt/backend/prompt-view-provider.ts

@@ -688,10 +688,6 @@ export class PromptViewProvider implements vscode.WebviewViewProvider {
               this.api_call_abort_controller.abort('Cancelled by user.')
               this.api_call_abort_controller = null
             }
-          } else if (
-            message.command == 'CANCEL_PROMPT_VIEW_API_CALLS_MANAGER_REQUEST'
-          ) {
-            this.prompt_view_api_calls_manager.cancel_api_call(message.id)
           } else if (message.command == 'GET_API_CONFIGURATIONS') {
             await handle_get_api_configurations(this)
           } else if (message.command == 'REORDER_API_CONFIGURATIONS') {

packages/ui/src/components/editor/prompt/Configurations/Configurations.module.scss

@@ -142,4 +142,14 @@
   > button {
     flex: 1;
   }
+
+  &--landscape-placeholder {
+    display: none;
+    visibility: hidden;
+    pointer-events: none;
+
+    @include landscape {
+      display: flex;
+    }
+  }
 }

packages/ui/src/components/editor/prompt/Configurations/Configurations.tsx

@@ -142,8 +142,7 @@ export const Configurations: React.FC<Configurations.Props> = (props) => {
     <div className={styles.container}>
       {props.configurations.length == 0 && (
         <div
-          className={styles.footer}
-          style={{ visibility: 'hidden', pointerEvents: 'none' }}
+          className={cn(styles.footer, styles['footer--landscape-placeholder'])}
         >
           <Button>{props.translations.add_new}</Button>
         </div>