Functional: Update Electronic Signature Screenshot

The Sikuli functional testing has been failing for some time when trying
to sign the lab order for the strep test.

Update the screenshot of the Electronic Signature label and text field
with a new image and an update path in the FunctionalTesting.html and .py

OSEHRA-Issue: http://issues.osehra.org/browse/OAT-59
Change-Id: I619998b1e52c8fc3e8def5dfa69f0119fc3049dd
Merge "Functional: Update Electronic Signature Screenshot"