Fix custom mapping doesn't work on dashboard (#29359)

...ters/reproductions/29347-remapped-field-values.cy.spec.js

...etabase_enterprise/sandbox/models/params/field_values.clj

...d/test/metabase_enterprise/sandbox/api/dashboard_test.clj

src/metabase/api/dashboard.clj

src/metabase/api/public.clj

src/metabase/models/params.clj

src/metabase/models/params/field_values.clj

test/metabase/api/dashboard_test.clj

test/metabase/api/embed_test.clj

test/metabase/api/public_test.clj