`get_{$taxonomy}` filter misfires when `$taxonomy` parameter is omitted

[dlh]

[34997] made the $taxonomy parameter to get_term() optional. However, when no $taxonomy is passed, no $taxonomy is available for the dynamic get_{$taxonomy} filter, so the less-exciting get_ filter is applied instead. Additionally, no $taxonomy is passed to the get_term filter.

The attached patch would set $taxonomy to that of the retrieved term before the get_term and get_{$taxonomy} filters are applied.

14162.3.patch:ticket:14162​ on the original ticket includes the same adjustment, but it seems to have been missed, or I am missing something.

[boonebgorges]

Thanks, @dlh. This was almost certainly an oversight when introducing WP_Term.

[boonebgorges]

In 44325:

Ensure that taxonomy name passed to get_term() filters is non-empty.

Since [34997], the $taxonomy parameter of get_term() has been
optional. This created cases where the $taxonomy parameter, used
to concatenate names for some filters and passed as a parameter to
others, would be empty. This changeset ensures that it's never
empty by falling back on the taxonomy of the located term.

Props dlh.
Fixes #45698.