Use 1-based indexing to return values

[mohamed-180]

Related to #1318

[t-kalinowski]

Thank you!
Can you please also update the roxygen docs (e.g., by inserting "(1-based)" where appropriate) and also a note in the NEWS?
If you're planning to also update the others listed in #1318, a simple as_axis() callback should be all that's needed for each of them (along with news and docs updates)

[t-kalinowski]

Thank you for the PR!

Changing indexing in keras was too much of a breaking change. This was deferred and implemented in the new package {keras3}.