Always check meridian flip before starting next capture

Summary: Diff D20150 had an unexpected side effect. The check for a meridian flip only took place at the beginning of each capture sequence and not before or after each capture. This diff fixes it by adding an additional meridian flip check before the next capture in a capture sequence is executed.

Test Plan:
Bug fix test: create a capture job with a single sequence having many captures. Slew the mount to a position is close to the meridian and start the capture. Expected result is, that the capture sequence is interrupted by a meridian flip and after the meridian flip the imaging session is continued.
Regression tests: Test meridian flip behaviour with scheduler running, capturing without scheduler and with an idle mount.

Reviewers: mutlaqja, TallFurryMan

Reviewed By: mutlaqja

Subscribers: kde-edu

Tags: KDE Edu

Differential Revision: https://phabricator.kde.org/D21034