selftests: net: Add tests to verify team driver option set and get.

selftests: net: Add tests to verify team driver option set and get.

There are currently no kernel tests that verify setting and getting
options of the team driver.

In the future, options may be added that implicitly change other
options, which will make it useful to have tests like these that show
nothing breaks. There will be a follow up patch to this that adds new
"rx_enabled" and "tx_enabled" options, which will implicitly affect the
"enabled" option value and vice versa.

The tests use teamnl to first set options to specific values and then
gets them to compare to the set values.

Signed-off-by: Marc Harvey <marcharvey@google.com>
Link: https://patch.msgid.link/20250905040441.2679296-1-marcharvey@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>