Misleading empty columns in project details report

[jaragunde]

Given a project with the following distribution of hours:

• week 1: 40h
• week 2: 40h
• week 3: 0h

Steps to reproduce:

1. Open project details for that project.
2. Click "view" with empty dates to see the full data.
3. Select start and end dates inside week 3, and click "view" again.

Expected result: weekly hours table is empty, no columns shown.

Actual result: weekly hours table has "week 1" and "week 2" columns, with 0 hours each.

The actual result is misleading, because those weeks do have hours assigned on them, although they are not shown because they fall outside of the selected report period.

Columns of the weekly hours table should be reset in any case when dates in the report are modified.