fix(html): add k-sr-only span inside empty pivotgrid cell #5096

Job	Run time
CI \| Visual	1s
CI \| Unit	1s
Status check > Unit	1s
Compile themes / run	47s
Lint scripts / run	45s
Lint styles / run (default)	1m 25s
Render test pages / verify	7s
Lint styles / run (bootstrap)	1m 23s
Lint styles / run (material)	1m 24s
Lint styles / run (classic)	1m 31s
Lint styles / run (fluent)	1m 6s
Render test pages / run	2m 30s
Status check > Lint scripts	1s
Status check > Lint styles	1s
Status check > A11y / prepare	1s
Create screenshots / run (default)	2m 27s
Create screenshots / run (bootstrap)	2m 14s
Create screenshots / run (material)	2m 27s
Create screenshots / run (classic)	2m 12s
Create screenshots / run (fluent)	2m 4s
Status check > A11y / run-checks (1)	2m 25s
Status check > A11y / run-checks (2)	2m 20s
Status check > A11y / run-checks (3)	2m 32s
Status check > A11y / run-checks (4)	2m 36s
Detect changes	14s
Status check > Visual	1s
	32m 36s

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