Add a test case to verify clipboard parsing of code completions surrounded by text

Author: robertpiosik

packages/vscode/src/commands/apply-chat-response-command/utils/clipboard-parser/test-cases/code-completion-with-text/code-completion-with-text.txt

@@ -0,0 +1,8 @@
+Some text before.
+
+```typescript
+// src/index.ts 25:5
+console.log("completion");
+```
+
+Some text after.