PT redesign: handle raw, change allocation and update golden tests

Refactored `MergeCodecsFromConfigurations` to use a multi-pass approach
(Primary+RTX, then RED, then FEC) to restore the expected payload type
allocation order for video RED and ULPFEC codecs.

Modified `BasicOfferAnswerPayloadTypesStable` to use a different golden
set when the `WebRTC-PayloadTypesInTransport` field trial is enabled,
accounting for the different payload type allocation order in the
redesign path. Added the new golden set for
`kWebRtcTipOfTreeWithPayloadTypeRedesign`.

Also cleaned up `auto` usage in several files to comply with the style
guide.

Added a specific `SetRawPacketization` mechanism to `TypedCodecVendor`
and `CodecVendor` to support the `packetization=raw` hack applied via
SDP munging. This ensures that subsequent offers generated in the
redesign path also include the `packetization=raw` parameter for the
affected codec.

This avoids adding generic backwards propagation of munged codec changes
while keeping this specific hack working.

Verified with a new unit test in `codec_vendor_redesign_unittest.cc`
and by verifying that `MungeRawPacketizationChangesSubsequentSections`
now passes.

Bug: webrtc:360058654, webrtc:412904801
Change-Id: Ic6e5a270304ecbd69cfeb805b209336081c33c62
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/475003
Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#47825}