Remove unneeded alt text from thumbnails as per lighthouse

[cjyabraham]

[cjyabraham]

I removed the alt text from two instances where an anchor element wrapped both the thumbnail image and the title of the content. I figure those alt tags would register as "redundant". Many other content items don't use an anchor element to wrap both image and title so I left those as is.

Pagespeed is registering this as fixed.