refactor(quic): remove quinn encryption (#1831)

* use quinn-plaintext
* remove server_cert in QUICTunnelListener
* remove some customized transport config
* leave max_concurrent_bidi_streams as default

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Cargo.lock

@@ -2217,6 +2217,7 @@ dependencies = [
  "prost-reflect-build",
  "prost-types",
  "quinn",
+ "quinn-plaintext",
  "rand 0.8.5",
  "rcgen",
  "regex",
@@ -6508,6 +6509,18 @@ dependencies = [
  "web-time",
 ]
 
+[[package]]
+name = "quinn-plaintext"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3e617feaeb6493018fa35fc47ae8b630ac8903d8159e9e747018841b99bad3d"
+dependencies = [
+ "bytes",
+ "quinn-proto",
+ "seahash",
+ "tracing",
+]
+
 [[package]]
 name = "quinn-proto"
 version = "0.11.12"