[Autofill PCC]: Optimize PCC Detection calling

PCC Detection feature should only be enabled if both conditions are satisfied.
1. flag:pcc_classification_enabled is enabled
2. Device has config: config_defaultFieldClassificationService defined.

In the absence of either of the above, PCC feature should be turned off.

Test: atest CtsAutoFillServiceTestCases
The above 'atest CtsAutoFillServiceTestCases' was ran in two cases
1. config_defaultFieldClassificationService not present on device.
2. config_defaultFieldClassificationService defined on the device.
Also, ran through Autofill usecase manually.
Bug: 279610519

Merged-In: I92f509b150586f7ad35580240a2981c1d31f10a9
Change-Id: I92f509b150586f7ad35580240a2981c1d31f10a9