docs: Update CO2 injection example

[dkachuma]

This PR updates the CO2 injection example to address the issues raised in #3660

The pvt files in this case were updated at #2933. However, the update to the co2flash.txt file was missed. I have therefore updated the example so that the actual files are referenced directly without having to duplicate them in the rst.

The update at #2933 changed the ranges of pressure and temperature used to generate the PVT tables. These new values are more correct because they include the surface conditions required by the well. I cannot go back to the old ranges because now geos has a check to ensure that the well operates within the range of the PVT data.

According to the change at #2933, and also at #1065, I suspect the original images were generated with a temperature range that was too low. This led to the gas density being higher and therefore the gas not being as buoyant. When this was corrected, the gas became more buoyant as can be seen with the new results.

I have edited the case to make the images look a bit more like the original. I have halved the vertical permeability to curtail the gas migration upwards and reduced the porosity to 0.05 to ensure that the gas reaches the surface. The updated example has the new updated images.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 57.43%. Comparing base (bbecb28) to head (b9a2168).
⚠️ Report is 62 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3661      +/-   ##
===========================================
- Coverage    57.57%   57.43%   -0.15%     
===========================================
  Files         1235     1234       -1     
  Lines       107102   106983     -119     
===========================================
- Hits         61669    61444     -225     
- Misses       45433    45539     +106     

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[jhuang2601]

@dkachuma Thanks for updating this case.
@margauxraguenel Please take a look on this fix.

[margauxraguenel]

Tested on our side, perfect!