75761 Added scrollbar example (cla: yes, d: api docs, d: examples, documentation, f: material design, f: scrolling, framework, waiting for tree to go green)

75764 ScrollController.jumpTo zero should not trigger the refresh indicator (cla: yes, f: material design, f: scrolling, framework, waiting for tree to go green)

75769 fix(flutter_driver): Properly declare socket as nullable (a: tests, cla: yes, framework, waiting for tree to go green)

75794 Fix for #75792 - allow use of Animator<Color?> with LinearProgressIndicator (cla: yes, f: material design, framework, waiting for tree to go green)

75796 Remove “unnecessary” imports in test/widgets (cla: yes, framework, waiting for tree to go green)