[reports] GET chart/<pk>/data api doesn't respect force parameter

[mayurnewase]

A clear and concise description of what the bug is. Api to get data of a saved chart used by reports to send csv data doesn't respect force parameter resulting in reports having stale data.

How to reproduce the bug

1. setup caching for data and report
2. create table chart, so it caches the data
3. change the data in the datasource without busrting cache of the chart
4. create report with csv and enable Ignore cache when generating screenshot
5. see the report having stale data.

Expected results

As Ignore cache when generating screenshot is enabled, report should have fresh data from datasource. Or this option is only for reports with screenshot as its name suggests?

Actual results

Report has stale data.

Screenshots

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Environment

(please complete the following information):

• browser type and version:
• superset version: 1.5.1 and 2.0
• python version: python --version
• node.js version: node -v
• any feature flags active: ALERT_REPORTS

Checklist

Make sure to follow these steps before submitting your issue - thank you!

• [ ] I have checked the superset logs for python stacktraces and included it here as text if there are any.
• [ ] I have reproduced the issue with at least the latest released version of superset.
• [ ] I have checked the issue tracker for the same issue and I haven't found one similar.

Additional context

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