Prevent `undefined method 'gravatar_url' for nil:NilClass` error in avatar component

[andrewmcodes]

Type of PR

• [ ] feature
• [ ] enhancement
• [x] bug fix
• [ ] other

Description

Provides some safety measures for nil users in the Avatar component, as well as some light refactoring.

Fixes #1324

Checklist

• [x] My code follows the style guidelines of this project & the tests are passing
• [x] I have performed a self-review of my own code
• [x] I have requested a review from another developer(s)

Screenshots

[codecov[bot]]

Codecov Report

Merging #1325 into master will increase coverage by 0.07%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1325      +/-   ##
==========================================
+ Coverage   34.76%   34.83%   +0.07%     
==========================================
  Files         345      345              
  Lines        7989     7995       +6     
==========================================
+ Hits         2777     2785       +8     
+ Misses       5212     5210       -2     

Impacted Files	Coverage Δ
app/components/application_component.rb	64.70% <100.00%> (+14.70%)	:arrow_up:
app/components/avatar_component.rb	100.00% <100.00%> (ø)
app/jobs/schedule_organization_report_job.rb	86.20% <0.00%> (ø)