Failing test for UTF-8 input

Digest::SHA 5.74 and later no longer silently take unicode strings and
process them byte by byte.  It will die and prevent further display of
the page with "Wide character in subroutine entry" in server logs.
Calculate the SHA1 of the encoded $$content

This prevents Digest::SHA::sha512_base64 from croaking with wide characters.
Similar to what's done for MD5 in
https://github.com/bestpractical/rt/blob/80bcdcfdea2988329a49bc6823f54da5d304762c/lib/RT/User.pm#L1000

Fixes I#30469
Merge branch '3.0/sha-utf-8-data' into 3.0-trunk
I forgot to munge META when changing version