Fix installing a downloaded update (#17812)
Fixes #17811
Follow-up to #17310
Summary of the issue:
Attempting to install a just-downloaded update fails on latest alphas.
Description of user facing changes
Update installation should work again
Description of development approach
Fixed several instances of property access on the `UpdateInfo` object
using snake_case instead of camelCase.
Testing strategy:
Created a portable from source, spoofing the version and update version
type:
```ps
./scons source version=2024.1 updateVersionType=stable
```
Ran the following tests:
1. Update and install immediately
1. Launch the portable
1. Check for updates, and download the update
1. When prompted, choose to install the update
1. Wait for the launcher to run, then cancel by answering No when asked
whether to update the portable
1. Update and install later manually
1. Launch the portable
1. Check for updates, and download the update
1. When prompted, choose to postpone the update
1. Exit NVDA via the exit dialog, and choose to install the pending
update
1. Wait for the launcher to run, then cancel by answering No when asked
whether to update the portable
1. Update and install later when prompted
1. Launch the portable
1. Check for updates, and download the update
1. When prompted, choose to postpone the update
1. Restart the portable
1. When prompted, choose to install the pending update
1. Wait for the launcher to run, then cancel by answering No when asked
whether to update the portable
Known issues with pull request:
None.
