Signal-Desktop: update to 5.6.2.

[reedts]

General

• This is a new package and it conforms to the quality requirements

Have the results of the proposed changes been tested?

• I use the packages affected by the proposed changes on a regular basis and confirm this PR works for me
• I generally don't use the affected packages but briefly tested this PR

[ScrelliCopter]

Works for me :)
Please squash your second commit into your first and rebase on master.

[reedts]

@ScrelliCopter Done :)!

[Veganizer]

Can you bump version from 5.4.1 to 5.6.2 maybe? :-)

[ericonr]

There is a failing patch, probably because of the change to default patching args. Please fix :)

[reedts]

@Veganizer @ericonr Bumped version to 5.6.2, fixed patch and rebased to current master

[ScrelliCopter]

Builds & runs on my end. Don't forget to update the version in the PR title.