fix(amazonq): full project scan command not working

[jpinkney-aws]

Problem

a tab id isn't getting created when you call status bar -> full project scan with /review causing the command to fail with "you cannot open more then 10 tabs"

Solution

create a new tab if tabId is undefined. This can only happen when agent commands are triggered via a command, since they don't know the tabId ahead of time

---

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