sentry: fix undefined error

[thelostone-mc]

Fixes

• Cannot read property 'length' of undefined
• Cannot read property 'now' of undefined
• Cannot read property 'style' of null
  
• 'Web3' is undefined
• compiledSplitter0 is not defined - on grants index page

[codecov]

Codecov Report

Merging #4583 into master will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4583      +/-   ##
==========================================
- Coverage   30.12%   30.09%   -0.04%     
==========================================
  Files         211      211              
  Lines       16954    16954              
  Branches     2290     2290              
==========================================
- Hits         5108     5102       -6     
- Misses      11648    11654       +6     
  Partials      198      198

Impacted Files	Coverage Δ
app/dashboard/embed.py	28.16% <0%> (-3.45%)	⬇️

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[danlipert]

Looks good but how was it tested?

[thelostone-mc]

@danlipert -> checking on which page the error appears -> recreate the same env and fix the error
All of them add an extra if check which would otherwise through undefined if it continued execution

[danlipert]

@thelostone-mc Sounds good but I worry that in squashing these alarms, we may introduce additional issues so I think it needs some solid manual testing. I'm down to do it in pre-deploy regression tests though, what do you think?