Consume core Penta updates: Divider

[tlabaj]

follow up to core issue patternfly/patternfly#6136

[kmcfaul]

Horizontal divider needs no changes.
Vertical divider needs a core fix (not displaying in a flex layout on react examples and core examples).

Keeping issue open for now until core update with the fix goes in.

[mcoker]

@kmcfaul @tlabaj this should be fixed in core, we added an example of the divider in a flex layout here - https://pf6.patternfly.org/components/divider#in-flex-layout