Fix emoting with emoji or pills (#8105)

* Fix emoting with emoji or pills

* Fix some slash command errors not being shown

* Re-enable mistakenly skipped SendMessageComposer tests

* Test emoting with non-text parts

src/SlashCommands.tsx

@@ -153,13 +153,11 @@ export class Command {
     public run(roomId: string, threadId: string, args: string): RunResult {
         // if it has no runFn then its an ignored/nop command (autocomplete only) e.g `/me`
         if (!this.runFn) {
-            reject(
+            return reject(
                 newTranslatableError(
                     "Command error: Unable to handle slash command.",
                 ),
             );
-
-            return;
         }
 
         const renderingType = threadId

src/editor/serialize.ts

@@ -181,7 +181,9 @@ export function textSerialize(model: EditorModel): string {
 }
 
 export function containsEmote(model: EditorModel): boolean {
-    return startsWith(model, "/me ", false) && model.parts[0]?.text?.length > 4;
+    const hasCommand = startsWith(model, "/me ", false);
+    const hasArgument = model.parts[0]?.text?.length > 4 || model.parts.length > 1;
+    return hasCommand && hasArgument;
 }
 
 export function startsWith(model: EditorModel, prefix: string, caseSensitive = true): boolean {