fix: dev: Make all ISC_LIST_FOREACH calls safe

Previously, `ISC_LIST_FOREACH` and `ISC_LIST_FOREACH_SAFE` were
two separate macros, with the _SAFE version allowing entries
to be unlinked during the loop. `ISC_LIST_FOREACH` is now also
safe, and the separate `_SAFE` macro has been removed.

Similarly, the `ISC_LIST_FOREACH_REV` macro is now safe, and
`ISC_LIST_FOREACH_REV_SAFE` has also been removed.

Merge branch 'each-isc-list-foreach' into 'main'

See merge request isc-projects/bind9!10479