Add cilium_enable_bbr flag for cilium

[cyclinder]

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/kind api-change
/kind bug
/kind cleanup
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/kind failing-test

/kind feature

/kind flake

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

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Does this PR introduce a user-facing change?:

network: Add cilium_enable_bbr flag for cilium bandwidth manager

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[k8s-ci-robot]

@cyclinder: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-kubespray-yamllint	30a0c5c	link	true	/test pull-kubespray-yamllint

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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