MDL-71305 core_question: Remove duplicate strings

lang/en/question.php

@@ -354,8 +354,6 @@ $string['defaultmark'] = 'Default mark';
 $string['errorsavingflags'] = 'Error saving the flag state.';
 $string['feedback'] = 'Feedback';
 $string['fillincorrect'] = 'Fill in correct responses';
-$string['flagged'] = 'Flagged';
-$string['flagthisquestion'] = 'Flag this question';
 $string['generalfeedback'] = 'General feedback';
 $string['generalfeedback_help'] = 'General feedback is shown to the student after they have completed the question. Unlike specific feedback, which depends on the question type and what response the student gave, the same general feedback text is shown to all students.
 
@@ -388,7 +386,6 @@ $string['markoutofmax'] = 'Mark {$a->mark} out of {$a->max}';
 $string['marks'] = 'Marks';
 $string['noresponse'] = '[No response]';
 $string['notanswered'] = 'Not answered';
-$string['notflagged'] = 'Not flagged';
 $string['notgraded'] = 'Not graded';
 $string['notshown'] = 'Not shown';
 $string['notyetanswered'] = 'Not yet answered';
@@ -451,7 +448,6 @@ $string['restoremultipletopcats'] = 'The backup file contains more than one top-
 $string['rightanswer'] = 'Right answer';
 $string['rightanswer_help'] = 'An automatically generated summary of the correct response. This can be limited, so you may wish to consider explaining the correct solution in the general feedback for the question, and turning this option off.';
 $string['saved'] = 'Saved: {$a}';
-$string['saveflags'] = 'Save the state of the flags';
 $string['settingsformultipletries'] = 'Multiple tries';
 $string['showhidden'] = 'Also show old questions';
 $string['showmarkandmax'] = 'Show mark and max';