tests: net: socket: Increase ztest stack size for offload_dispatcher

The test suite is failing on qemu_cotext_a9 due to stack overflow.
Apparently this issue can also be observed on main after enabling
STACK_SENTINEL, however the test only started crashing after TCP
changes.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
1 file changed