Fix the schema by updating the data type

[sgandhi1311]

Description of change

• The QuickBooks documentation indicates that Qty values are represented as decimal numbers.
• Previously, Qty was defined as an integer, which leads to inaccuracies when handling non-integer quantities (e.g., 1.5 or 0.75).
• Doc Ref - https://developer.intuit.com/app/developer/qbo/docs/api/accounting/all-entities/invoice#:~:text=lines%20per%20invoice.-,The%20invoice%20object,-ATTRIBUTES
• JIRA - TDL-26710

Manual QA steps

Risks

Rollback steps

• revert this branch

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