VSCE: add integration test cases for remote code browsing

Created by: tjkandala

From https://github.com/sourcegraph/sourcegraph/pull/33921/files#diff-33e3cb58530689d363c25d4e706788a47973998a90c6bb99341eac2c24d491a8R67-R70.

Assert that:

• Clicking on a search result opens an editor with the correct file
• Sourcegraph extension hover providers work correctly on remote files
• Clicking on a file in remote file tree opens an editor with the correct file