feat(amazonq): Implement inline completion test (#7752)

Implemented the inline completion test within inline.test.ts. This test
suite does not need any special helper functions but I added a bunch of
new functions in generalUtils.ts

Note: I added the types@selenium-webdriver because we have started to
interact with elements outside of the Amazon Q webview (ie. the text
editor)

---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).
- License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Author: laura-codess

package-lock.json

@@ -83,6 +83,7 @@
     },
     "dependencies": {
         "@types/node": "^22.7.5",
+        "@types/selenium-webdriver": "^4.1.28",
         "buffer": "^6.0.3",
         "jaro-winkler": "^0.2.8",
         "mocha": "^11.7.1",