Logs of the instance don't display properly if the form is submitted by enter instead of mouse click on the "view log" button

[lucaa]

Steps to reproduce

1. on the homepage of the admin tools, click on the "View last n lines of log..." button, in the Files sent section
2. in the dialog that is displayed, fill in a number of lines (e.g. 100)

3. hit the enter key of the keyboard after having filled in the number

Expected behavior
The last 100 lines of log are displayed

Actual behavior
An 'internal server error" is displayed, and the resulting page doesn't have a number of lines in the URL

Environment (please complete the following information):

• OS: Ubuntu
• Browser chrome]
• XWiki version 16.10.11
• App version 1.3

Additional context
Note that if, instead of enter, the "View" button is clicked with the mouse, the visualisation of the logs works correctly: