Correct syntax error stopping update check dialog from opening when a previous update had been downloaded and there are incompatible add-ons. (#15285)
Fixes #15028
Fixes #15284
Summary of the issue:
the Check For Updates dialog fails to open if a previous update has already been downloaded (is pending) and there are incompatible add-ons.
This is due to a syntax error when concatinating a string.
Description of development approach
Remove the invalid plus character.