[CTS] Increase timeout for idle broadcasts when starting user

Continuous CTS runs were hitting the timeout. Increase timeout to 10
minutes as installing package + starting user trigger many broadcasts to
be sent.

Bug: 122305663
Test: atest CtsBackupHostTestCases
Change-Id: I1a33cccdb16e8462263d3bd80485d9ecb55bad3a
1 file changed