fix(amazonq): fix uploading file method error handling for /doc

[KevinDing1]

Problem

For /doc, file upload method threw incorrect error message when workspace too large

Solution

Fix uploading file method error handling for /doc

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[github-actions]

• This pull request modifies code in src/* but no tests were added/updated.
  • Confirm whether tests should be added or ensure the PR description explains why tests are not required.