Merge changes Ida388b6f,I9ed00a76,I2d37fe56,I81633390,Ia16926b4, ... into main

* changes:
  Register reserved offer
  Add L2capNetworkSpecifier to blanket offer
  Add blanket offer to L2capNetworkProvider
  Add empty L2capNetworkProvider
  Implement matching semantics for L2capNetworkSpecifier
  Do not allow L2CAP specifier with ROLE_SERVER and remote address set
  Do not redact PSM from L2capNetworkSpecifier
  Use IntRange for setPsm
  Improve documentation of L2capNetworkSpecifier
  Have setRemoteAddress accept a Nullable remoteAddress