podman: [APIv2] building container with isolation=default started failing after #9246

Is this a BUG REPORT or FEATURE REQUEST? (leave only one on its own line)

/kind bug

Description

Trying to find regressions by exercising the APIv2 trough docker-py’s test suite (see #5386) I came across a regressions in the BuildTest::test_build_isolation test.

Building containers with isolation=default started failing with commit 19507d0ffe8cda0a69f056838556f471fd9e61fa.

Steps to reproduce the issue:

cat > Dockerfile <<EOF
FROM scratch
CMD sh -c "echo \'Deaf To All But The Song\'
EOF

1. tar cf test.tar Dockerfile

2. curl -sS --unix-socket /var/run/user/1000/podman/podman.sock -XPOST 'http://localhost/v1.40/build?t=isolation&isolation=default' -H "Content-Type: application/tar" --data-binary '@test.tar'

Describe the results you received:

Run against commit 19507d0ffe8cda0a69f056838556f471fd9e61fa:

{"cause":"schema: error converting value for \"isolation\"","message":"schema: error converting value for \"isolation\"","response":400}

Describe the results you expected:

Run against commit 2bf13219f587d769400f26aeaed05930c34ce3d7:

{"stream":"STEP 1: FROM scratch\n"}
{"stream":"STEP 2: CMD sh -c \"echo \\'Deaf To All But The Song\\'\n"}
{"stream":"STEP 3: COMMIT isolation\n"}
{"stream":"Getting image source signatures\n"}
{"stream":"Copying blob sha256:4ca545ee6d5db5c1170386eeb39b2ffe3bd46e5d4a73a9acbebc805f19607eb3\n"}
{"stream":"Copying config sha256:fe9067e46ed83a50d10c196a74bed82e66fc11a714240b001f1e70c82d6eaec9\n"}
{"stream":"Writing manifest to image destination\n"}
{"stream":"Storing signatures\n"}
{"stream":"--\u003e fe9067e46ed\n"}
{"stream":"fe9067e46ed83a50d10c196a74bed82e66fc11a714240b001f1e70c82d6eaec9\n"}
{"stream":"Successfully built fe9067e46ed8\n"}