Only print stopping server if already printed URL

[leo]

This ensures we only print this message if we already printed the server URL:

It also prints a nice newline to make it look better:

[codecov-io]

Codecov Report

Merging #2249 into canary will increase coverage by 0.02%.
The diff coverage is 77.77%.

@@            Coverage Diff             @@
##           canary    #2249      +/-   ##
==========================================
+ Coverage   10.38%   10.41%   +0.02%     
==========================================
  Files         246      246              
  Lines        9030     9037       +7     
  Branches      986      988       +2     
==========================================
+ Hits          938      941       +3     
- Misses       7972     7975       +3     
- Partials      120      121       +1

Impacted Files	Coverage Δ
src/commands/dev/lib/dev-server.ts	39.65% <77.77%> (+0.2%)	⬆️
src/commands/dev/lib/builder-cache.ts	65.57% <0%> (-1.38%)	⬇️

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[thasophearak]

LGTM 🙌