Load TDR data based on checking whether the file of interest exists, instead of all TDR files

[RuaridhMacd]

…not all TDR files

Description

Dolphyn only loads TDR inputs if all TDR files are present instead of just the file of interest. This check isn't consistent, as the list of "all" TDR files is different in different places. This PR changes the check to only be based on the TDR flag and whether the file of interest exists

Fixes issue \

222

Type of change

Please delete options that are not relevant.

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration.

• [x] Example_Systems/SmallNewEngland/OneZone
• [x] Example_Systems/SmallNewEngland/ThreeZones

Test Configuration:

• OS: MacOS M2
• Solver: Gurobi
• Julia version: 1.9.3
• Solver version: 10.0

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] I have run tests with my code to avoid compatibility issues
• [x] Any dependent changes have been merged and published in downstream modules

[RuaridhMacd]

@magiovanniello please check that this works for you now

[bennettm]

Looks good. Approve.