Fix production flows from parameter scenario's

[mrvisscher]

Parameter scenario's were giving unexpected results because all the flows that were being extracted from them were labeled as 'Technosphere'-types even though they could also be 'Production'-types. This lead to erroneous outcomes whenever the output flow of an activity has a formula.

• fixes #1231

Checklist

• [x] Keep pull requests small so they can be easily reviewed.
• [x] Update the documentation, please follow the numpy style guide.
• [x] Update tests.
• [x] Categorize the PR by setting a good title and adding one of the labels: bug, feature, ui, change, documentation, breaking, ci as they show up in the changelog.
• [x] Link this PR to related issues by using closing keywords.
• [x] Add a milestone to the PR for the intended release.
• [ ] Request a review from another developer.

[coveralls]

coverage: 50.688%. remained the same when pulling 7f7fcbafb98d0e69d84f4c81def005a7bf0c9baf on mrvisscher:parameter-scenario-flow-type-fix into 0955df9ad3644251c9511f73a3998cdefc99df74 on LCA-ActivityBrowser:master.