Fix plot bug

[1abdelhalim]

Changes Made:

• plot_track:

  • Fixed a bug causing a KeyError when accessing specific column names (longitude (degrees_east) and latitude (degrees_north)). Updated to use generic column names (longitude and latitude).

  • Aligned function expectations with the output of the standardise_df function from the fetchers.py module.

• plot_transect:

  • Improved the plot_transect function to enhance readability and usability.

  • Updated the y-axis label to "Pressure (dbar)" for clarity.

  • Modified the data source from "depth (m)" to "pressure" (df["pressure"]) to accurately represent the plotted data.

[ocefpaf]

@1abdelhalim this PR has some conflicts and we will wait until GSoC results are in to work on this. Closing for now but we will re-open accordingly. Note that to fix this, we want to standardize the columns names and not try to catch for a specific case. That is b/c the request can change to have the units, making the original code here correct.