Clarify that dialed numbers are unformatted.

Adding docs clarification so ImsService impls know they need to format
the dialed numbers to E164 or whatever format is required for SIP
message generation.

Test: Docs only change
Fixes: 198818889
Change-Id: Icac9e7e120c83f179f65adb54b87ca224e9b4f71
1 file changed