CLC-3207 Missing bCourses section links with unprefixed CCN strings

https://jira.media.berkeley.edu/jira/browse/CLC-3207

The bug is that a bCourses course site wasn't being correctly associated with an official campus enrollment in the My Classes widget.

In My Classes, we figure out which campus courses a bCourses site belongs to by checking the embedded CCNs in the bCourses section IDs. A while ago we started prefixing all CCN strings with zeroes to fill out to five digits. But older Canvas sections, or Canvas sections which were created manually, may lack the prefixes. E.g., they might be "SEC:2014-B-3963" instead of "SEC:2014-B-03963". Since we were doing a string match, the old-style CCN strings in the Canvas data didn't match the new-style CCN strings in the campus course data.

The fix is to compare as number instead.