PIM-1653 Prevent displaying scientific notation when exporting metric

```
Bug fix: yes
Feature addition: no
Backwards compatibility break: no
Unit test passes: yes
Behat scenarios passes: no
Checkstyle issues: no
ChangeLog updated: no
Documentation PR:
Fixes the following jira:
 - PIM-1653
```

Converting `double(0.00005)` into `string` gives `5E-5`