Increase sleep to 5s after starting NVDA in chromeTests

[seanbudd]

Link to issue number:

Follow up from #12293

Summary of the issue:

Chrome was still losing focus in systetests

These builds failed with the 2s sleep included due to taskbar gaining focus

• https://ci.appveyor.com/project/NVAccess/nvda/builds/38799243/tests
• https://ci.appveyor.com/project/NVAccess/nvda/builds/38800164/tests

Description of how this pull request fixes the issue:

Increase sleep time to 5s.

Testing strategy:

Low impact, see if system tests continue to fail due to taskbar gaining focus

Known issues with pull request:

• Docker popups may still block the build: prevent Chrome losing focus during systests #12293 (comment) (I plan to follow up add better logging for this, and try to set them to re-run on appveyor)
• 5s of sleep might not be long enough (we have confidence that 10s is)
• Lint checking occasionally blocks builds due to a failed merge (I plan to follow up and fix this soon)

Change log entries:

None

Code Review Checklist:

• Pull Request description is up to date.
• Unit tests.
• System (end to end) tests.
• Manual tests.
• User Documentation.
• Change log entry.
• Context sensitive help for GUI changes.