Reland "Adding a restriction for legal RID values."

This is a reland of 07f3279a730980583403b78c3762c5d246d1d9be

Original change's description:
> Adding a restriction for legal RID values.
>
> According to the spec, RID values should be constrained to only
> alpha-numeric values. This was not enforced in our implementation to
> allow for more flexibility.
> It has been brought to our attention that some values that we currently
> consider legal (such as the '~', '=' ';' characters) might cause confusion
> with the simulcast syntax that uses these characters to indicate other
> meanings.
> What's worse, is that some characters, when used in RIDs (such as
> \u{1f937} \u{1f4a9} and \u{1f926}) cause uncontrollable laughter for some
> users which might also be a health hazard.
> This change resolves these issues by restricting RIDs to alpha-numeric.
>
> Bug: webrtc:10491
> Change-Id: I16e262c87525d0289764beacd098e1525a355463
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/132061
> Reviewed-by: Steve Anton <steveanton@webrtc.org>
> Commit-Queue: Amit Hilbuch <amithi@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#27499}

TBR=steveanton@webrtc.org

Bug: webrtc:10491
Change-Id: I856581306a9258480ee9184f12b55c2a23dd8636
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/131983
Commit-Queue: Amit Hilbuch <amithi@webrtc.org>
Reviewed-by: Amit Hilbuch <amithi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27530}

pc/sdp_serializer_unittest.cc

@@ -469,6 +469,10 @@ const char* kRidDescriptionMalformedStrings[] = {
     "1 send pt=",
     "1 send pt=abc",
     "1 recv ;;",
+    "~1 recv",
+    "1$2 send",
+    "1=2 send",
+    "1* send",
 };
 
 INSTANTIATE_TEST_SUITE_P(RidDescriptionDeserializationErrors,