Defer webbrowser import

[blink1073]

Fixes #1094

[codecov]

Codecov Report

Base: 80.39% // Head: 80.40% // Increases project coverage by +0.01% 🎉

Coverage data is based on head (90d6a40) compared to base (e9735fc).
Patch coverage: 0.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1095      +/-   ##
==========================================
+ Coverage   80.39%   80.40%   +0.01%     
==========================================
  Files          68       68              
  Lines        8297     8297              
  Branches     1652     1652              
==========================================
+ Hits         6670     6671       +1     
+ Misses       1198     1197       -1     
  Partials      429      429              

Impacted Files	Coverage Δ
jupyter_server/serverapp.py	80.21% <0.00%> (ø)
...ter_server/services/kernels/connection/channels.py	59.91% <0.00%> (+0.21%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[kevin-bates]

LGTM

[blink1073]

@meeseeksdev please backport to 1.x