QGrpc{Call,Channel}Options: remove noexcept from the new 6.12 getters

requestCompression() and acceptedCompressionAlgorithms() dereference
d_ptr, which is a precondition rather than something these functions
verify: calling them on a moved-from object is not valid. A function
with a precondition should not be noexcept.

supportedCompressionAlgorithms() has no d-pointer, but queries
QDecompressHelper. Pass QBAV's as arguments to correctly provide
noexcept guarantees.

Found during the Qt 6.12 API review.

Pick-to: 6.12
Change-Id: I414ebf222c7900df572f6dee4cd4204791f4597f
Reviewed-by: Marc Mutz <marc.mutz@qt.io>