Feature - Add count for total tests done uptil the latest data fetched.

Created by: huzefa-amura

Description of PR

• We can now see the total number of tests done until the latest data fetched from covid19 API. It also shows the delta of tests.
• The total tests done count can be found besides the Deceased count.

Screenshot

Relevant Issues: https://github.com/covid19india/covid19india-react/issues/688

Type of PR

• Bugfix
• New feature

Checklist

• Compiles and passes lint tests
• Properly formatted
• Tested on desktop
• Tested on phone

Screenshots