[Enhancement]: skip creating index when there is no querynode

[longjiquan]

Is there an existing issue for this?

• I have searched the existing issues

What would you like to be added?

Skip creating index when there is no querynode.

Why is this needed?

Avoid the index version rollbacked to 0.

Anything else?

No response

[xiaofan-luan]

why we skip create index when there is no qn?

[czs007]

@xiaofan-luan Currently ,we query the all the QueryNode to determine the index engine version of Knowhere.

[xiaofan-luan]

if there are no querynodes, simply use latest version as a fallback?

[xiaofan-luan]

assuming all the new brought up nodes should be new versions