Update request time scraping for compatibility with I895cd03f0

Change I895cd03f0 to mediawiki/core changes the way request timing data is
outputted from an HTML comment specifying request time in seconds to a
JavaScript configuration variable which specifies request time in milliseconds.
This change makes ApiSandbox compatible with both formats.

Change-Id: Id54b2bd30abdde29675df4609304157cb08069b4