1 vdiffr test is not ignored if vdiffr is not installed

[Yuri05]

== Failed tests =========================================================================================================
-- Error (test-font-label.R:57): Long texts are properly handled in labels -----
<packageNotFoundError/error/condition>
Error in `loadNamespace(x)`: there is no package called ‘vdiffr’
Backtrace:
    x
 1. \-base::loadNamespace(x) at test-font-label.R:57:2
 2.   \-base::withRestarts(stop(cond), retry_loadNamespace = function() NULL)
 3.     \-base (local) withOneRestart(expr, restarts[[1L]])
 4.       \-base (local) doWithOneRestart(return(expr), restart)
-- Error (test-font-label.R:104): Markdown syntax is not supported because Label and Font overwrite its with the FontFace argument --
<packageNotFoundError/error/condition>
Error in `loadNamespace(x)`: there is no package called ‘vdiffr’
Backtrace:
    x
 1. \-base::loadNamespace(x) at test-font-label.R:104:2
 2.   \-base::withRestarts(stop(cond), retry_loadNamespace = function() NULL)
 3.     \-base (local) withOneRestart(expr, restarts[[1L]])
 4.       \-base (local) doWithOneRestart(return(expr), restart)
-- Error (test-plot-grid.R:104): Plot Grid can have very long texts and contain plots with very long titles --
<packageNotFoundError/error/condition>
Error in `loadNamespace(x)`: there is no package called ‘vdiffr’
Backtrace:
    x
 1. \-base::loadNamespace(x) at test-plot-grid.R:104:2
 2.   \-base::withRestarts(stop(cond), retry_loadNamespace = function() NULL)
 3.     \-base (local) withOneRestart(expr, restarts[[1L]])
 4.       \-base (local) doWithOneRestart(return(expr), restart)

[ FAIL 3 | WARN 3 | SKIP 9 | PASS 330 ]