fixing user profile schema for new keycloak to work with mnp-checkout

[ddelpiano]

Closes MC-207

Implemented solution

added stripe_uid to the keycloak user profile so that mnp-checkout attribute setting api call will not fail silently.
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How to test this PR

for an existing deployment delete the namespace and re-run the pipeline to deploy, check from realm settings -> user profile -> attributes if stripe_uid is present in the list of attributes

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