Fix generating the redirect url

[juliusknorr]

Fix #1852

[codecov]

Codecov Report

Merging #1972 (48c15ff) into master (8d3be14) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #1972      +/-   ##
============================================
+ Coverage     67.53%   67.58%   +0.04%     
  Complexity      249      249              
============================================
  Files            22       22              
  Lines           690      691       +1     
============================================
+ Hits            466      467       +1     
  Misses          224      224              

Impacted Files	Coverage Δ	Complexity Δ
lib/Controller/ContactsController.php	100.00% <100.00%> (ø)	2.00 <0.00> (ø)

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[welcome]

Thanks for your first pull request and welcome to the community! Feel free to keep them coming! If you are looking for issues to tackle then have a look at this selection: https://github.com/nextcloud/contacts/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22
Most developers hang out on IRC. So join #nextcloud-contacts and #nextcloud-dev on Freenode for a chat!

[juliusknorr]

Is #nextcloud-dev still a thing 🤔 ?

[skjnldsv]

Guess not