rcc

chore: Fix vignette building if tibble is missing #2721

Job	Run time
Smoke test: stock R	3m 30s
Check matrix	4s
rcc: ${{ matrix.os }} (${{ matrix.r }}) ${{ matrix.desc }}	0s
Without bit64	1m 44s
Without DBI	1m 51s
Without debugme	1m 53s
Without DiagrammeR	1m 52s
Without dplyr	1m 44s
Without formattable	2m 9s
Without ggplot2	1m 54s
Without lubridate	2m 17s
Without nanotime	1m 49s
Without nycflights13	2m 1s
Without palmerpenguins	1m 45s
Without scales	1m 51s
Without stringi	1m 53s
Without tibble	1m 55s
Without units	2m 21s
Without vdiffr	2m 3s
	34m 36s

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