Don't report warning for header line in imported master item Excel file

[mountaindude]

Ignore first line wrt warnings:

➜  tools ./ctrl-q master-item-import --host 192.168.100.109 --app-id a3e0f5d2-000a-464f-998d-33d333b175d7 --auth-user-dir LAB --auth-user-id goran --auth-type cert --file-type excel --file ./ctrl-q-testdata.xlsx --sheet Sales --col-ref-by name --col-item-type "Master item type" --col-master-item-name "Master Item Name" --col-master-item-descr "Description" --col-master-item-label "Label" --col-master-item-expr "Expression" --col-master-item-tag "Tag"

2022-10-13T18:30:43.820Z info: Import master items from definitions in Excel file "./ctrl-q-testdata.xlsx"
2022-10-13T18:30:44.288Z warn: Found an unknown master item type: "Master item type". Ignoring this line in the imported file.
2022-10-13T18:30:44.301Z info: Updated existing measure "No. of sold units"
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