Minor: Request copy assignment operator.

[KBaichoo]

Signed-off-by: Kevin Baichoo kbaichoo@google.com

Commit Message: The copy assignment operator is being invoked for SocketOptionName implicitly. Explicitly request it.
Additional Description:
Risk Level: N/A
Testing: NA
Docs Changes: NA
Release Notes: NA
Platform Specific Features: NA
[Optional Runtime guard:]
[Optional Fixes #Issue]
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It seems to be breaking for Clang 14. See:

Step #3 - "compile-afl-address-x86_64": �[1m./envoy/network/socket.h:26:3: �[0m�[0;1;31merror: �[0m�[1mdefinition of implicit copy assignment operator for 'SocketOptionName' is deprecated because it has a user-declared copy constructor [-Werror,-Wdeprecated-copy]�[0m
Step #3 - "compile-afl-address-x86_64":   SocketOptionName(const SocketOptionName&) = default;
Step #3 - "compile-afl-address-x86_64": �[0;1;32m  ^
Step #3 - "compile-afl-address-x86_64": �[0m�[1msource/common/network/socket_option_impl.cc:52:14: �[0m�[0;1;30mnote: �[0min implicit copy assignment operator for 'Envoy::Network::SocketOptionName' first required here�[0m

[KBaichoo]

/retest

[repokitteh-read-only]

Retrying Azure Pipelines:
Retried failed jobs in: envoy-presubmit

🐱

Caused by: a #18865 (comment) was created by @KBaichoo.

see: more, trace.

[asraa]

Thanks for the fix!