Improve experience when FS installer crashes

[yoshiask]

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• Have you checked if similar request have already been reported?

Description

The Fluent Store installer up to 0.4.0 prints all of its log output to a text box in the installer window. However, this log output is inaccessible when an error occurs due to a message box that blocks the main window and closes the entire installer on dismiss. This makes it impossible for users to submit the log output with their bug report, instead relying on incomplete screenshots.

Alternative solutions

One or multiple of the following solutions may be taken:

1. Change the error dialog such that clicking "OK" doesn't close the installer. It may either stay on the "installing" page displaying an error state, or navigate to an entirely new error page.
2. Drop a log file in %TEMP% and ask if the user wants to open it.

Relevant Assets

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