[Tails-dev] Remove known issues about Mac UEFI 32-bit

I'm putting tails-bugs and mercedes508 in copy as I know they know more
about Mac support than anybody else, but the discusion is of interest to
tails-dev.

I see on #8471 that support for 32-bit UEFI was added in Tails 1.5, but
the known issues page still read:

« Any Mac with 32-bit EFI may not succeed in booting Tails USB stick
created by Tails Installer. »

The last update to this line dates back from July 2, before 1.5.

Shall I remove this bullet point?