Misc: More DuckStation backports

[stenzek]

Description of Changes

• Bumps SDL version for Flatpak, since both Jordan and I forgot about it.
• Simplifies the page fault handler logic, also provides the host with whether it was a write or read.
• Stops the crash handler from leaking zombie PCSX2 processes when it crashes. Hopefully this'll fix the random "permission denied" error some users get when updating.
• Fix remove game directory/excluded path tool button being enabled without a selection.

Rationale behind Changes

See above.

Suggested Testing Steps

Make sure games still boot.
Make sure when adding/removing a game/exclusion directory, the remove button behaves as expected.