Increase dbus timeout for gcu

[ganglyu]

Why I did it

GNMI test failed on some sonic devices, root cause is gcu performance.

How I did it

Increase dbus timeout.

How to verify it

Run end to end test.

Which release branch to backport (provide reason below if selected)

• [ ] 201811
• [ ] 201911
• [ ] 202006
• [ ] 202012
• [ ] 202106
• [ ] 202111

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[ganglyu]

/azpw run sonic-net.sonic-gnmi

[mssonicbld]

/AzurePipelines run sonic-net.sonic-gnmi

[azure-pipelines[bot]]

Azure Pipelines successfully started running 1 pipeline(s).