[docs] Solve Firefox middle click issue

[paol]

Closes #14618

[mui-pr-bot]

Details of bundle changes.

Comparing: 000def8...3a8124d

bundle	parsed diff	gzip diff	prev parsed	current parsed	prev gzip	current gzip
@material-ui/core/Paper	0.00%	0.00%	83,040	83,040	21,410	21,410
@material-ui/core/Paper.esm	0.00%	0.00%	76,728	76,728	20,462	20,462
@material-ui/core	0.00%	0.00%	484,797	484,797	130,083	130,083
@material-ui/core/styles/createMuiTheme	0.00%	0.00%	16,235	16,235	5,159	5,159
@material-ui/lab	0.00%	0.00%	295,473	295,473	86,174	86,174
@material-ui/styles	0.00%	0.00%	63,755	63,755	18,119	18,119
@material-ui/system	0.00%	0.00%	15,915	15,915	3,938	3,938
colorManipulator	0.00%	0.00%	2,290	2,290	838	838
Button	0.00%	0.00%	212,888	212,888	61,970	61,970
Modal	0.00%	0.00%	211,086	211,086	61,681	61,681
@material-ui/core/Popper	0.00%	0.00%	146,815	146,815	46,826	46,826
@material-ui/core/useMediaQuery	0.00%	0.00%	9,386	9,386	3,563	3,563
docs.main	0.00%	0.00%	676,085	676,099	205,101	205,111
docs.landing	0.00%	0.00%	48,963	48,963	10,275	10,275
packages/material-ui/build/umd/material-ui.production.min.js	0.00%	0.00%	320,431	320,431	84,703	84,703

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