fix unsqueeze cannot work on more than 1 dynamic_shape dimensions

[lanluo-nvidia]

Description

Fixes # (issue)
#2916
unsqueeze cannot support more than 1 dynamic dimensions

Type of change

Please delete options that are not relevant and/or add your own.

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code follows the style guidelines of this project (You can use the linters)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas and hacks
• I have made corresponding changes to the documentation
• I have added tests to verify my fix or my feature
• New and existing unit tests pass locally with my changes
• I have added the relevant labels to my PR in so that relevant reviewers are notified
• [ ]

[peri044]

LGTM. minor comment