update @tabler/core to 1.2.0

[orthagh]

Description

Following #19335

Previous issues seem fixed:

• alerts are ok now (important warning still have a crappy contrast)
• The accordion (especially on the right panel of the ticket view) is okay. The title heights are a bit too big, but this should be easily fixable. (changing h2 into `div), edit fixed

There are still a few ul > li changes of spacing that can be viewed in:

• general left menu,
• answer button (split action) of a ticket,
• top right menu

It should be easy to fix, too.

Found another thing in console, a bootstrap is not defined, but it seems from a minor thing, everything so far seems to work properly

[cedric-anne]

Found another thing in console, a bootstrap is not defined

Fixed by the latest commit.