How to change ripple effect to not overlap with the tab's shape?

The image below is an example of when a tab is long pressed but it shows an undesirable rectangle-shaped grey ripple effect.

long pressed active tab and long pressed inactive tab

How do I change its shape so that it has the same shape as the tab?

Here is my current code:

build method:

@override
  Widget build(BuildContext context) {
    return DefaultTabController(
      length: 2,
      child: Scaffold(
        body: CustomScrollView(
          slivers: [
            SliverAppBar(
              title: Text('Task n\' Note'),
              pinned: true,
              floating: true,
              foregroundColor: Colors.black,
              backgroundColor: Colors.white,
              bottom: TabBar(
                unselectedLabelColor: Colors.blueAccent,
                indicatorSize: TabBarIndicatorSize.label,
                indicator: BoxDecoration(
                    borderRadius: BorderRadius.circular(25.0),
                    color: Colors.blueAccent),
                tabs: [
                  _buildTab('Tasks'),
                  _buildTab('Notes'),
                ],
              ),
            )
          ],
        ),
      ),
    );

_buildTab method:

Widget _buildTab(String title) {
    return Tab(
      child: Align(
        alignment: Alignment.center,
        child: Text(title),
      ),
    );
  }