Fix bugs in create_objective_function

[an-altosian]

1. alphaWeight is not used anywhere in the function.
2. The nodes column in the weights dataframe always contains integers instead of the actual node names.
3. According to cplex, the maximum length of each line is 560, see here.

[gabora]

Hi @an-altosian,

Thank you for the proposed changes!

The alphaWeight was intentionally removed from the code. While it still appears as an input in some functions, it is not used anywhere. Accordingly, alphaWeight is not exposed to users and does not appear in the CARNIVALdefaultOptions.

I noticed that while the main branch passed the tests, the proposed pull request fails many unit tests on Linux:
[ FAIL 30 | WARN 0 | SKIP 14 | PASS 105 ]

Additionally, please note that we are not actively developing or maintaining the R version of CARNIVAL. For a more up-to-date and actively supported framework, we recommend checking out CORNETO, a Python-based implementation.

Best regards,