envoy-1.36+: request_body_buffer_limit with internal_redirect_policy regression

[pgeler]

Description:
After 1.36 release. Most likely caused by 369ace2.
HCM with internal_redirect_policy cannot process requests larger than request_body_buffer_limit, while previous versions were able to stream such requests upstream.
Repro steps:
in our case HTTP/1.1 -> EnvoyA(1.36) ->HTTP2-> EnvoyB(1.35) ->HTTP/1.1-> target
EnvoyA is default passthrough HTTP proxy with internal_redirect_policy, with default configuration buffer limit is 1MB.
POST HTTP requests larger than 1MB stuck, incompletely delivered and timeout through upstream.

Config:

                      routes:
                        - match:
                            prefix: "/"
                          route:
                            cluster: upstream
                            retry_policy:
                              retry_on: "connect-failure,refused-stream,reset-before-request"
                              num_retries: 3
                            internal_redirect_policy:
                              max_internal_redirects: 5
                              redirect_response_codes: [307]