VIIl1b reader fails for testdata

[ninahakansson]

Describe the bug
The VII reader fails for testdata

To Reproduce

# Your code here
from satpy import Scene
from satpy.utils import debug_on
debug_on()
filename = "W_DE-AIRBUSDS-Friedrichshafen,SAT,SGA1-VII-1B-RAD_C_EUM_20200929104726_G_D_20070912102741_20070912102841_T_X____.nc"
from satpy import Scene
scn_ = Scene(reader='vii_l1b_nc', filenames=[filename])
scn.load(['vii_10690'])

Expected behavior
To be able to read the data without errors.

Actual results
Text output of actual results or error messages including full tracebacks if applicable.

First error:
Don't know how to open the following files: {'/VII_L1B_TDP_v1_to_OSISAF/W_DE-AIRBUSDS-Friedrichshafen,SAT,SGA1-VII-1B-RAD_C_EUM_20200929104726_G_D_20070912102741_20070912102841_T_X____.nc'}
Second error (after fixing file name pattern):
KeyError: 'data/calibration_data/integrated_solar_irradiance'

Screenshots
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Environment Info:

• OS: Linux
• Satpy Version: 0.24.0

Additional context
Add any other context about the problem here.