bus array_idx is causing issues with enum arrays

[s3bs]

cocotb-bus/src/cocotb_bus/bus.py

Lines 89 to 90 in 7962b53

	if array_idx is not None:
	handle = handle[array_idx]

previous implementation prior to cocotb/cocotb#2304 used a different way and that worked

ie.

# works
getattr(dut, "my_signal[0]")  
# doesn't work
handle = getattr(dut, "my_signal")
handle[0]
-->  IndexError: my_signal(GPI_ENUM) is not indexable.  Unable to get object at index 0

Signal that is accessed is
my_enum_e [SIZE-1:0] my_signal

using Linux, xcelium 24.03-s004, cocotb 1.4

the above works with the build in bus.py from cocotb 1.4 but not with this library

[s3bs]

persists in v1.8.0