Update scale restrictions in NN API ops docs

NN API relaxed scale restrictions to improve compatibility with TF Lite.

Updated ops:
- CONV_2D
- DEPTHWISE_CONV_2D
- TRANSPOSE_CONV_2D
- GROUPED_CONV_2D
- FULLY_CONNECTED

Test: mma
Bug: 127427474
Change-Id: I9dabd27b21679b99d638c364464d815e1c199787