File name with special characters should not be allowed

Preconditions:

• Test Run should exist.
• Test Run should contain test steps.

Steps to reproduce:

1. Go to Test Run.
2. Select one test step.
3. Copy a screenshot into your clipboard (CTRL-C).
4. Do CTRL-V to paste the screenshot as evidence.
5. Input a name containing special characters (see attachment to check special characters).
6. Click Save.

Expected result:

• Evidence is not saved.
• An error is displayed indicating screenshot cannot be saved because file name contains special characters.

Actual result:

• Evidence is saved.
• File name contains special characters.
• When some special characters are inputted (i.e. "\") file name is empty.