Rename "img-txt-mini" to "image-text-mini" so it matches its corresponding component name

[mmmavis]

To follow our existing convention and to make sure things can be easily looked up, let's rename img-txt-mini to image-text-mini so it matches its corresponding component name.

• selector names in foundation.mozilla.org/network-api/networkapi/wagtailpages/templates/wagtailpages/blocks/image_text_mini.html
• file name and selector names in foundation.mozilla.org/source/sass/components/img-txt-mini.scss
• other img-txt-mini instances in the codebase

[Sharma-palak]

@mmmavis ,can I take this issue

[mmmavis]

Hi @Sharma-palak thanks for offering help! If you already know how to spin up the project locally and you think this ticket description provides enough instructions, feel free to take this on!

[Sharma-palak]

@mmmavis plzz review the pr

[alanmoo]

@youriwims Can you take the code review over the finish line?

[youriwims]

Sure can 👍

[youriwims]

Closed via #3438