refactor: plugins allow sandbox destroy

[alexbarnsley]

Summary

Fixes a bug where events do not get destroyed when plugins are disabled.

Checklist

• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged

[codecov]

Codecov Report

Merging #1578 into develop will increase coverage by 0.19%.
The diff coverage is 77.27%.

@@             Coverage Diff             @@
##           develop    #1578      +/-   ##
===========================================
+ Coverage    45.52%   45.71%   +0.19%     
===========================================
  Files          274      274              
  Lines         6832     6875      +43     
  Branches      1337     1346       +9     
===========================================
+ Hits          3110     3143      +33     
- Misses        3561     3570       +9     
- Partials       161      162       +1

Impacted Files	Coverage Δ
...r/services/plugin-manager/sandbox/route-sandbox.js	33.33% <ø> (ø)	⬆️
...ces/plugin-manager/sandbox/font-awesome-sandbox.js	100% <ø> (ø)	⬆️
...erer/services/plugin-manager/setup/themes-setup.js	86.66% <ø> (ø)	⬆️
...services/plugin-manager/setup/wallet-tabs-setup.js	100% <ø> (ø)	⬆️
...er/services/plugin-manager/sandbox/http-sandbox.js	100% <ø> (ø)	⬆️
...ervices/plugin-manager/setup/font-awesome-setup.js	0% <ø> (ø)	⬆️
.../services/plugin-manager/setup/menu-items-setup.js	91.66% <ø> (ø)	⬆️
...er/services/plugin-manager/setup/webframe-setup.js	100% <ø> (ø)	⬆️
...services/plugin-manager/sandbox/storage-sandbox.js	100% <ø> (ø)	⬆️
.../plugin-manager/sandbox/profile-current-sandbox.js	80% <ø> (ø)	⬆️
... and 16 more

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