UI tests: tst_ChatFlow - Update `The user can send a sticker after installing a free pack` to be stable

[noeliaSD]

Description

The following scenario has been disabled from CI The user can send a sticker after installing a free pack
since it may be flaky due to undeterministic network conditions and 3rd party infura response.

Review how we can make it estable and enable it again in the CI.

[Valentina1133]

Closing it, because we don't work on old squish tests anymore. Something is already automated and something will be automated in new framework