data_dictionary_builder missing SourceFrom for LINST instruments

[xlecours]

Describe the bug
When running data_dictionary_builder.php, SourceFrom is empty when there is no table line in the .linst file.
This is happening when the table is in the .meta file.

To Reproduce

cp raisinbread/instruments/bmi.* project/instruments/
cd tools
sed '1s/^/{-@-}/' -s ../project/instruments/bmi.linst >> ip_output.txt
cd exporters
php data_dictionary_builder.php

One way to fix that would be to also cat the .meta file into ip_output.txt. But data_dictionary_builder crashes when encountering the jsondata line. Just skipping the line would work.

Additional context
Noticed while testing #8845