refactor some tests, remove onboarding tutorial & preferences

[fedekunze]

Description:

Thank you! 🚀

---

For contributor:

• Added entries in PENDING.md with issue # and GitHub username
• Reviewed Files changed in the github PR explorer
• Attach screenshots of the UI components on the PR description (if applicable)
• Scope of work approved for big PRs

For reviewer:

• Manually tested the changes on the UI

[codecov]

Codecov Report

Merging #2255 into develop will decrease coverage by 0.05%.
The diff coverage is 81.81%.

@@             Coverage Diff             @@
##           develop    #2255      +/-   ##
===========================================
- Coverage    96.67%   96.61%   -0.06%     
===========================================
  Files          108      108              
  Lines         2313     2306       -7     
  Branches       115      118       +3     
===========================================
- Hits          2236     2228       -8     
+ Misses          65       64       -1     
- Partials        12       14       +2

Impacted Files	Coverage Δ
app/src/renderer/vuex/modules/index.js	100% <ø> (ø)	⬆️
app/src/renderer/vuex/modules/session.js	100% <ø> (ø)	⬆️
app/src/renderer/components/common/Page404.vue	100% <ø> (ø)	⬆️
app/src/renderer/vuex/getters.js	90.56% <ø> (-0.18%)	⬇️
app/src/renderer/components/common/TmField.vue	95.65% <66.66%> (-4.35%)	⬇️
...src/renderer/components/common/PagePreferences.vue	92.85% <87.5%> (-7.15%)	⬇️
app/src/renderer/components/wallet/PageWallet.vue	96.29% <0%> (-3.71%)	⬇️
...pp/src/renderer/components/network/PageNetwork.vue	100% <0%> (ø)	⬆️
.../renderer/components/governance/PageGovernance.vue	100% <0%> (ø)	⬆️
app/src/renderer/components/common/TmPage.vue	100% <0%> (ø)	⬆️
... and 4 more

[codecov]

Codecov Report

Merging #2255 into develop will increase coverage by 0.05%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           develop    #2255      +/-   ##
===========================================
+ Coverage    96.68%   96.73%   +0.05%     
===========================================
  Files          108      106       -2     
  Lines         2321     2297      -24     
  Branches       115      116       +1     
===========================================
- Hits          2244     2222      -22     
+ Misses          65       63       -2     
  Partials        12       12

Impacted Files	Coverage Δ
app/src/renderer/components/common/ToolBar.vue	100% <ø> (ø)	⬆️
app/src/renderer/vuex/getters.js	90.56% <ø> (-0.18%)	⬇️
app/src/renderer/vuex/modules/index.js	100% <ø> (ø)	⬆️
app/src/renderer/vuex/modules/session.js	100% <ø> (ø)	⬆️
app/src/renderer/components/common/Page404.vue	100% <ø> (ø)	⬆️
app/src/renderer/components/common/TmField.vue	100% <100%> (ø)	⬆️