wasm: add config setting to control StopIteration behavior (#40213)

Add PluginConfig.allow_on_headers_stop_iteration config field to control
the behavior of WasmFilter when plugin onRequestHeaders and
onResponseHeaders callbacks return a value of
FilterHeadersStatus::StopIteration.

If allow_on_headers_stop_iteration is false (the default), then in cases
where a Wasm plugin onRequestHeaders or onResponseHeaders callback
returns FilterHeadersStatus::StopIteration, WasmFilter will maintain its
current behavior of translating that response code to
FilterHeadersStatus::StopAllIterationAndWatermark.

If allow_on_headers_stop_iteration is true, then WasmFilter will avoid
any translation of FilterHeadersStatus::StopIteration, and will pass it
through to HCM unmodified, which allows Wasm plugins to inspect request
or response body data before deciding how to handle/transform request or
response headers.

For details, see [Envoy Wasm / Proxy-Wasm support for
FilterHeadersStatus::StopIteration](https://docs.google.com/document/d/1Whd1C0k-H2NHrPOmlAqqauFz6ObSTP017juJIYyciB0/edit?usp=sharing).
This PR implements [Option B: WasmFilter config
knob](https://docs.google.com/document/d/1Whd1C0k-H2NHrPOmlAqqauFz6ObSTP017juJIYyciB0/edit?tab=t.0#bookmark=id.5wxldlapsp54),
building on proxy-wasm/proxy-wasm-cpp-host#434.

Note that this config knob is a stopgap until upcoming v0.3.0 of the
Proxy-Wasm ABI adds more comprehensive support for StopIteration and
body buffering, per proxy-wasm/spec#63.

Additional Description:

This change updates the proxy-wasm-cpp-host dependency since it depends
on proxy-wasm/proxy-wasm-cpp-host#434, which was
recently merged there.

Signed-off-by: Michael Warres <mpw@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ 274d68f02971c1cf0da1628991126e8ebd307d25

Author: update-envoy[bot]

envoy/extensions/wasm/v3/wasm.proto

@@ -6,6 +6,7 @@ import "envoy/config/core/v3/backoff.proto";
 import "envoy/config/core/v3/base.proto";
 
 import "google/protobuf/any.proto";
+import "google/protobuf/wrappers.proto";
 
 import "envoy/annotations/deprecation.proto";
 import "udpa/annotations/status.proto";
@@ -148,7 +149,7 @@ message EnvironmentVariables {
 }
 
 // Base Configuration for Wasm Plugins e.g. filters and services.
-// [#next-free-field: 9]
+// [#next-free-field: 10]
 message PluginConfig {
   // A unique name for a filters/services in a VM for use in identifying the filter/service if
   // multiple filters/services are handled by the same ``vm_id`` and ``root_id`` and for
@@ -192,6 +193,10 @@ message PluginConfig {
 
   // Configuration for restricting Proxy-Wasm capabilities available to modules.
   CapabilityRestrictionConfig capability_restriction_config = 6;
+
+  // Whether or not to allow plugin onRequestHeaders and onResponseHeaders callbacks to return
+  // FilterHeadersStatus::StopIteration.
+  google.protobuf.BoolValue allow_on_headers_stop_iteration = 9;
 }
 
 // WasmService is configured as a built-in ``envoy.wasm_service`` :ref:`WasmService