oidmap_clear_with_free()

As part of the conversion away from oidmap_clear(), switch the
missing_objects map to use oidmap_clear_with_free().

missing_objects stores struct missing_objects_map_entry instances,
which own an xstrdup()'d path string in addition to the container
struct itself. Previously, rev-list manually freed entry->path
before calling oidmap_clear(&missing_objects, true).

Introduce a dedicated free callback and pass it to
oidmap_clear_with_free(), consolidating entry teardown into a
single place and making cleanup semantics explicit. This improves
clarity and maintainability.

Signed-off-by: Seyi Kuforiji <[email protected]>

Replace the use of oidmap_clear(&seen_at_depth, 1) in
filter_trees_free() with oidmap_clear_with_free().

The seen_at_depth map stores heap-allocated struct
seen_map_entry objects. Previously, passing 1 relied on
oidmap_clear() internally calling free() on each entry.

Convert this to the explicit oidmap_clear_with_free() API
and provide a typed free_seen_map_entry() helper to free
each container entry.

This makes the ownership and cleanup policy explicit and
removes reliance on the legacy boolean free_entries
parameter.

Signed-off-by: Seyi Kuforiji <[email protected]>

Replace the direct oidmap_clear() call in odb_free() with
oidmap_clear_with_free(), and introduce a free_replace_map_entry()
helper to properly free each struct replace_object stored in the map.

This centralizes cleanup logic and ensures entries are released
correctly via a dedicated callback.

Signed-off-by: Seyi Kuforiji <[email protected]>

Switch cleanup of the string_entry oidmap to
oidmap_clear_with_free() and introduce a free_string_entry()
helper to properly free each allocated struct string_entry.

This aligns with the ongoing migration to use the callback-based
oidmap cleanup API.

Signed-off-by: Seyi Kuforiji <[email protected]>