childrenCollapsable disabled for splitter in manager.ui

This is a very small "bug fix" in manager.ui, I just disabled the childrenCollapsable property in the splitter separating the log viewer/ options buttons from the tab view with all the managers.

Background: Previously, when moving the splitter in any direction the log viewer and the options button were collapsed and the user was unable to get them back - the user needed to restored kstars in order to change settings there which is terrible during a capturing session. Now, the log view and options button are never collapsed and are always available. Support for collapsing them is now disabled, but I cannot see any benefit for collapsing a button which is needed to control/change settings unless I'm able to bring it back.

In fact, I tried a lot of options how to overcome this Qt issue. The only other way I could think of would be to create a custom splitter widget with perhaps a lot of new issues introduced. This splitter issue was discussed in the INDI forum and I had myself several nights where I used the splitter by mistake to increase the log view just to get it collapsed entirely. From my point of view it seems this is the best option for now - maybe collapsing can be enabled again using a much newer Qt version.