Envoy Mobile always requires dfp_mixed_scheme for the TLS and cleartext DFP clusters. While dfp_mixed_scheme defaults to true, some environments (like within Google), force it to false for the Envoy use case, so we force it back to true here in Envoy Mobile, so we don't break the mobile integration tests.

Once general use of dfp_mixed_scheme is fixed everywhere, we can revert this commit.

Tested by changing dfp_mixed_scheme to FALSE_RUNTIME_GUARD and running the mobile xDS integration tests:

cd mobile
bazelisk test --test_output=streamed --cache_test_results=no //test/common/integration:rtds_integration_test

Request variables

Key	Value
ref	ea4306c288a6472aef9946ef166bf759008edf01
sha	16e0506
pr	31586
base-sha	917d6c9
actor	@abeyad
message	mobile: Force the dfp_mixed_scheme flag to true in Envoy Mobile...
started	1704218714.554573
target-branch	main
trusted	false

Container image/s (as used in this CI run)

Envoy version (as used in this CI run)