shortcut.js: Don't launch shortcut if Ctrl or Alt is pressed

See #2383.
This launched some shortcuts while using
some web browser features.
6 jobs for feature-c/prevent_spurious_shortcuts in 5 minutes and 46 seconds (queued for 9 seconds)
Status Name Job ID Coverage
  Test Quality
failed code_quality #5705
allowed to fail

00:00:06

failed code_quality #5589
allowed to fail

00:00:01

 
  Test Unit
passed test_browser_unit #5590

00:00:02

 
  Test Functional
failed test_browser-functional #5591

00:05:36

 
  Deploy
skipped deploy #5592
manual stop_deploy #5593
allowed to fail manual
 
Name Stage Failure
failed
test_browser-functional Test Functional There is an unknown failure, please try again
3 runs, 6 assertions, 0 failures, 1 errors, 0 skips

generating ci files
make[2]: *** [functional] Error 1
make[2]: Leaving directory `/home/gitlab_ci_multi_runner/builds/66984086/0/vidjil/vidjil/browser/test'
make[1]: *** [headless] Error 2
make[1]: Leaving directory `/home/gitlab_ci_multi_runner/builds/66984086/0/vidjil/vidjil/browser/test'
make: *** [headless_browser] Error 2
ERROR: Build failed: exit status 1
failed
code_quality Test Quality There is an unknown failure, please try again
germline/rattus-norvegicus/IGLJ_downstream.fa
germline/rattus-norvegicus/IGLJ.fa
germline/rattus-norvegicus/IGLV.fa
germline/IMGT_RELEASE
browser/js/germline.js
make[1]: Leaving directory `/home/gitlab_ci_multi_runner/builds/66984086/0/vidjil/vidjil/germline'
$ jshint browser/js/*.js
bash: line 52: jshint: command not found
ERROR: Build failed: exit status 1