18456 Deleted obsolete feature flags

[severinbeauvais]

Issue #: bcgov/entity#18456

Description of changes:

• app version = 4.7.6
• deleted obsolete "alteration-ui-enabled" FF
• deleted obsolete "change-ui-enabled" FF
• deleted obsolete "conversion-ui-enabled" FF
• removed flag usage from Alteration.vue
• removed flag usage from Change.vue
• removed flag usage from Conversion.vue
• removed flag usage from SpecialResolution.vue

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of the bcrs-entities-create-ui license (Apache 2.0).