Bug 32283: Correct capitalisation of opac > OPAC

Bug 32283: Correct capitalisation of opac > OPAC

Test plan
Step 1: Navigate to admin>Identity Providers
Step 2: Add new domain
Step 3: For 'Allow opac' setting, verify that opac is lower case in both label and description
Step 4: Apply patch
Step 5: Navigate to admin>Identity Providers
Step 6: Add new domain
Step 7: For 'Allow OPAC' setting, verify that OPAC is upper case in both label and description

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>