tap: remove unused dependency. (#7580)

Description: Remove an unused dependency from tap. This makes a build warning go away.
Risk Level: low
Testing: build
Docs Changes: N/A
Release Notes: N/A

Signed-off-by: Ismo Puustinen <ismo.puustinen@intel.com>

Mirrored from https://github.com/envoyproxy/envoy @ 101f8157fe06d78262d0b3c07cf1c2b7c8e72c98

envoy/service/tap/v2alpha/BUILD

@@ -10,7 +10,6 @@ api_proto_library_internal(
         "//envoy/api/v2/core:base",
         "//envoy/api/v2/core:grpc_service",
         "//envoy/api/v2/route",
-        "//envoy/type/matcher:string",
     ],
 )
 

envoy/service/tap/v2alpha/common.proto

@@ -3,7 +3,6 @@ syntax = "proto3";
 import "envoy/api/v2/route/route.proto";
 import "envoy/api/v2/core/base.proto";
 import "envoy/api/v2/core/grpc_service.proto";
-import "envoy/type/matcher/string.proto";
 
 import "google/protobuf/wrappers.proto";