Adding permission READ_SUBSCRIPTION_PLANS

Adding permission READ_SUBSCRIPTION_PLANS, which will be used to read
the status and end date of a subscription plan. In the future,
this permission can be reused for any fields to be accessible to apps
beyond the carrier app.

Flag: com.android.internal.telephony.flags.subscription_plan_allow_status_and_end_date

Test: device boot
Bug: 357272015
Change-Id: I08228847bef0c6d37f7cc8dc7875f4d5d72c7f7b
Merged-In: I08228847bef0c6d37f7cc8dc7875f4d5d72c7f7b