Orchagent - reassert bridge port admin state on VLAN member re-add

[johanna-nexthop]

What I did

Updated PortsOrch::addBridgePort() to reassert the bridge port state when reusing an existing bridge port:

• Set SAI_BRIDGE_PORT_ATTR_ADMIN_STATE to true.
• Restore the host interface VLAN tag mode to SAI_HOSTIF_VLAN_TAG_KEEP.
• Handle SAI failures using the existing status-processing logic.
• Return failure if restoring the host interface VLAN tag mode fails.

Why I did it

A bridge port can remain present after a failed or incomplete removal while being left administratively disabled or with an incorrect host interface VLAN tag mode.

When the VLAN member is added again, the existing bridge port is reused. Previously, its state was not reasserted, which could leave the port disabled or incorrectly configured.

This change ensures that reused bridge ports are restored to the expected operational state before continuing.

How I verified it

Added the addBridgePortReassertsAdminStateOnReuse unit test, which:

• Creates a bridge port for Ethernet0.
• Forces its admin state to false.
• Re-adds the port using the existing bridge port.
• Verifies that SAI_BRIDGE_PORT_ATTR_ADMIN_STATE is restored to true.

Details if related

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[mssonicbld]

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[mssonicbld]

Hi, there are workflow run(s) waiting for approval, you may be first-time contributor. I will notify maintainers to help approve once PR is approved. Thanks!

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