Automatic merge from submit-queue
Fix initial exec terminal dimensions
**What this PR does / why we need it**:
Delay attempting to send a terminal resize request to docker until after
the exec has started; otherwise, the initial resize request will fail.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#47990
**Special notes for your reviewer**:
**Release note**:
```release-note
NONE
```
