Email alert text updates

[dracos]

Improves the text on update alert signup for phone-only users (stops referring to email alerts), and fixes an issue whereby a phone-only user could sign up for a local alert but wouldn't ever get anything, so instead ask for email and do a merge, like the verify email step would do, if that makes sense. [skip changelog]

[codecov]

Codecov Report

Merging #3367 (877a41d) into master (71082a1) will increase coverage by 0.00%.
The diff coverage is 91.89%.

❗ Current head 877a41d differs from pull request most recent head 41d7a36. Consider uploading reports for the commit 41d7a36 to get more accurate results

@@           Coverage Diff           @@
##           master    #3367   +/-   ##
=======================================
  Coverage   82.38%   82.38%           
=======================================
  Files         324      324           
  Lines       21431    21457   +26     
  Branches     3227     3234    +7     
=======================================
+ Hits        17655    17678   +23     
- Misses       2737     2738    +1     
- Partials     1039     1041    +2     

Impacted Files	Coverage Δ
perllib/FixMyStreet/DB/Result/User.pm	95.50% <85.71%> (-0.84%)	⬇️
perllib/FixMyStreet/App/Controller/Tokens.pm	88.29% <92.85%> (+0.34%)	⬆️
perllib/FixMyStreet/App/Controller/Alert.pm	92.27% <100.00%> (+0.15%)	⬆️
perllib/FixMyStreet/Script/Alerts.pm	90.96% <100.00%> (+0.40%)	⬆️
web/cobrands/fixmystreet-uk-councils/alloy.js	90.09% <0.00%> (-1.00%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 71082a1...41d7a36. Read the comment docs.

[struan]

☎️