Find pattern widget: incorrect processing of patterns names and comments in the pattern widget

There are some issues in the processing of patterns names and comments in the pattern widget.

1. Turn on the "Use pattern name" option but do not enter any pattern names in the pattern widget. Run the find task, save results to annotations.
Current state: annotations are not presented in the annotations tree view, but they are drown on the panoramic view. If you remove a document that contains the annotation table object, UGENE crashes.

2. Remove the annotation name in the annotations widget ("misc_feature" by default), turn on the "Use pattern name" option.
Current state: you can't start the search even the pattern name is defined in the pattern widget.

3. If pattern name is empty, but pattern name start symbol is presented, the appropriate pattern will be ignored.
An example:

>pattern1
ACGT             // this pattern will be found
>
AAAA             // this pattern will be ignored

4. One can set an unacceptable pattern name, that will be used as annotation name: it can contain incorrect symbols, it can be too long.

5. A new find task starts on every attempt to change text in the pattern widget, even if only a pattern name or a comment was redacted. A new search should start only if a pattern was changed.