Plugin Directory Admin: Fix links for Helpscout

[Ipstenu]

Two things

1) You need to double escape percents when you use them as spaces here, or else the string replace won't work
2) Removing an errant bracket

[SergeyBiryukov]

In 8545:

Plugin Directory, Author Card: Correct links to Help Scout, remove a stray bracket.

Props Ipstenu.
Fixes #4340.