Update VE core submodule to master (b5102a8)

New changes:
7f61ab3 Localisation updates from https://translatewiki.net.
003221a Follow-up I4f080228: Re-remove PNG and minimisation-related files from OOjs UI
7b0f9ee build: Update devDependencies related to Karma
3983e8a Actually remove ve.instances
674a024 Fix typo in MobileContext
7bba15f Remove this.$element on destroy but don't nullify
bee267f Revert "Follow-up 2075a46: Fix RTL image build by embedding after flipping"
b5102a8 Localisation updates from https://translatewiki.net.

Change-Id: Ib4313449ea5e6799ca193a9809279b8f2b057400
Merge "Update VE core submodule to master (b5102a8)"