Column.get(map=) support dicts with partial keys

[hagenw]

This updates audformat.Column.get(map=) to only raise an error if the requested mapping scheme is not available in all dictionaries of the scheme labels and not just in some.

Let's start with:

import audformat

db = audformat.Database('db')
db.schemes['speaker'] = audformat.Scheme(
    'int',
    labels={
        0: {'age': 35, 'gender': 'female'},
        1: {'age': 26},
    },
)
db['files'] = audformat.Table(audformat.filewise_index(['f1', 'f2']))
db['files']['speaker'] = audformat.Column(scheme_id='speaker')
db['files']['speaker'].set([0, 1])

Now we get

>>> db['files']['speaker'].get(map='location')
...
ValueError: Cannot map 'speaker' to 'location'. Expected one of ['age', 'gender'].

but the following no longer raises an error

>>> db['files']['speaker'].get(map='gender')
file
f1    female
f2      <NA>
Name: gender, dtype: string

---

The text regarding when we raise a ValueError was not completely specific before:

so I would not call this a breaking change, but a bug fix.

[codecov]

Codecov Report

Merging #403 (a832356) into main (5152318) will not change coverage.
The diff coverage is 100.0%.

Files	Coverage Δ
audformat/core/column.py	100.0% <100.0%> (ø)