Fixed emissions display when not measured

[jess-farmer]

Description of work

Fixes #1221

Changes fitting report so that Emissions value is listed as 'N/A' when the emissions table option is not selected. I have also updated the options_template.ini so that the emissions table is not deactivated, as measuring emissions is no longer painfully slow.

Testing Instructions

1. Run Fitbenchmarking without emissions table option, and check fitting report.

Checklist

• The title is of a format appropriate for a line in future release notes.
• I have added the appropriate tags to the PR.
• My PR represents one logical piece of work.
• My PR fully fixes the issue linked. If new issues have been created, what are they?
• I have added the appropriate tests to cover code that has been added.
• I have updated the documentation in the relevant places to cover the changes.

[github-actions]

Unit & System Test Results

  4 files  ±0    4 suites  ±0   6m 37s ⏱️ +9s
507 tests ±0  499 ✅ ±0   8 💤 ±0  0 ❌ ±0 
968 runs  ±0  914 ✅ ±0  54 💤 ±0  0 ❌ ±0 

Results for commit f30c652. ± Comparison against base commit cf9d1f1.

♻️ This comment has been updated with latest results.

[coveralls]

coverage: 90.668% (-0.01%) from 90.682%
when pulling f30c652 on fix_emissions_display
into cf9d1f1 on master.

[RabiyaF]

I tested it with and without the emissions tables and it works as expected 👍🏼