Show block description for gallery block for 0 images

[StuartFeldt]

Description

Gallery block is updated to show block description regardless of how many images are selected. Relates to #2023

How Has This Been Tested?

Manually tested, ran all test suites

Types of changes

UX updates

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows has proper inline documentation.

[codecov]

Codecov Report

Merging #2924 into master will decrease coverage by 0.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #2924      +/-   ##
==========================================
- Coverage   34.07%   34.06%   -0.02%     
==========================================
  Files         192      192              
  Lines        5675     5677       +2     
  Branches      996      997       +1     
==========================================
  Hits         1934     1934              
- Misses       3165     3166       +1     
- Partials      576      577       +1

Impacted Files	Coverage Δ
blocks/library/gallery/block.js	11.11% <0%> (-0.66%)	⬇️

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[youknowriad]

Nice 👍