fix: stop total budget from updating when daily budget is changed

[andrewmcodes]

Type of PR

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

Description

Changing the daily budget on bundled campaigns was dynamically updating the total budget, which we don't want.

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 #1305 into master will decrease coverage by 0.01%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1305      +/-   ##
==========================================
- Coverage   34.53%   34.51%   -0.02%     
==========================================
  Files         344      344              
  Lines        7955     7952       -3     
==========================================
- Hits         2747     2745       -2     
+ Misses       5208     5207       -1     

Impacted Files	Coverage Δ
app/models/concerns/campaigns/budgetable.rb	70.45% <100.00%> (+0.12%)	:arrow_up: