Fix #340 - only bar access_token as header

Proposed changes

Untested change, but this should allow the authzforce location to be queried using

curl -X GET \ 
  'http://keyrock/user?access_token={{access_token}}&app_id={{app_id}}&authzforce=true'

As was possible prior to Keyrock 8.4.0

Types of changes

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[x] Bugfix (non-breaking change which fixes an issue)
[ ] New feature (non-breaking change which adds functionality)
[ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

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[x] I have read the CONTRIBUTING doc
[x] I have signed the CLA
[ ] I have added tests that prove my fix is effective or that my feature works
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[ ] Any dependent changes have been merged and published in downstream modules

Further comments

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ging / fiware-idm