fix(bridge/authz/exhook): no need to drop invalid certs

[JimMoen]

revert parts of #8872. remove useless code.

[coveralls]

Pull Request Test Coverage Report for Build 3050554873

• 4 of 4 (100.0%) changed or added relevant lines in 3 files are covered.
• 26 unchanged lines in 11 files lost coverage.
• Overall coverage increased (+0.03%) to 77.554%

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Files with Coverage Reduction	New Missed Lines	%
apps/emqx_authn/src/simple_authn/emqx_authn_jwt.erl	1	85.8%
apps/emqx_slow_subs/src/emqx_slow_subs.erl	1	77.42%
apps/emqx/src/emqx_broker.erl	1	82.42%
apps/emqx/src/emqx_frame.erl	1	88.41%
apps/emqx/src/emqx_limiter/src/emqx_limiter_server.erl	1	89.08%
apps/emqx/src/emqx_logger_textfmt.erl	1	47.37%
apps/emqx/src/emqx_router_helper.erl	1	86.27%
apps/emqx/src/emqx_cm.erl	2	88.99%
apps/emqx/src/emqx_channel.erl	3	86.36%
apps/emqx/src/emqx_reason_codes.erl	7	92.65%

Totals
Change from base Build 3049658358:	0.03%
Covered Lines:	20720
Relevant Lines:	26717

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💛 - Coveralls