Increase the timeout for arm64 jobs
Increase the timeout for arm64 jobs

The original timeout is 3660 for both openstack-tox-py38-arm64 and
openstack-tox-py39-arm64, change it to 4800.

Related-Bug: #1949476
Related-Bug: #1949704
Change-Id: I2b0d2c8b60af0ab7398f38151ff0f62e451e7e3e

mahak/neutron,openstack/neutron,mahak/neutron,openstack/neutron,mahak/neutron,openstack/neutron