Colour contrast problems on the dashboard page

[jonkri]

Describe the bug
The colours used under All time and Last 7 days under All reports do not satisfy the WCAG colour contrast requirements (according to https://color.review/). The colors displayed on the page are #F4A140, #62B356 and #4FADED. See also the colours array in web/js/dashboard.js. Perhaps the icons in web/cobrands/fixmystreet.com/images/ should be updated as well.

To Reproduce
Steps to reproduce the behavior:

1. Visit All reports (/reports)
2. Notice the colour contrast between for text that is not black, and the white background colour

Expected behavior
The colour contrasts should satisfy the relevant requirements. Perhaps AA (4.5:1) would suffice.

Screenshots

Desktop (please complete the following information):
Irrelevant.

Smartphone (please complete the following information):
Irrelevant.

Additional context
Sufficient colour contrasts contributes to accessibility.