ngf-pattern with multiple file-extensions using spaces, not working

[TiagoFuelber]

Hi Daniel.

I figured out that when using ngf-pattern with spaces, the pattern match doesn't work correctly, because it includes the space in the regex pattern.

Example:

ngf-pattern='.xls, .xlsx, .csv'

Then when I try to upload .xlsx or .csv files it says it's not a valid file extension.

Inside the file validation, when it converts the string to regex, it doesn't remove spaces, so the regex pattern output would be: (^.*\.xls$)|(^ \.xlsx$)|(^ \.csv$). The subgroup 2 and 3 are including spaces.

[TiagoFuelber]

Hi Daniel, can I make the a PR with the fix?