Package updates shouldn't cause test failures unless behavior changes

[gadenbuie]

There are more than a few places where we have embedded package versions into our tests, which means that package updates for key packages can cause our tests to fail. Two recent examples:

• Fix snaps 2023-11-27 #247
• Update snaps 2023-11-28: crosstalk was updated #248

There may be a path forward in adding a compare= function as an argument to app$expect_values(), similar to the compare argument of app$expect_screenshot() (added in rstudio/shinytest2#231). We could have a function, e.g. shinycoreci::compare_json_ignore_pkg_versions() that would strip package versions before comparing.