[RTT] Condition RTT Controller on availability of a STA mode

Condition creation of the RTT controller on the chip being in a mode
which can support a STA (whether one is already created or one could
be created).

This is the default behavior on currently supported Wi-Fi devices.

Note: this is part of the reference HAL implementation - it is not
expected to reflect behavior of all devices. Vendors may and should
replace or modify the reference HAL implementation.

Bug: 79565105
Bug: 111218083
Test: ACTS RangeApSupporting11McTest:test_rtt_in_and_after_softap_mode
Change-Id: If76b6598acb22f7821b34f7f1c8ae2873a6dac1d