Rename the custom recovery passphrase well-known to match the merged schema

The merged element-enterprise#261 well-known schema advertises the feature
under custom_recovery_passphrase (no _settings/_requirements suffix), so the
parser previously looking for custom_recovery_passphrase_settings would never
activate the flow. Update the @SerialName and drop the narrow "Requirements"
suffix from the type — the block is now general, extensible feature settings —
to mirror the .pkl CustomRecoveryPassphrase class. Bumps the enterprise
submodule to the matching consumer change.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

libraries/wellknown/api/src/main/kotlin/io/element/android/libraries/wellknown/api/CustomRecoveryPassphrase.kt

@@ -8,11 +8,11 @@
 package io.element.android.libraries.wellknown.api
 
 /**
- * Server-driven requirements for a user-chosen recovery passphrase. Today the only rule
- * is a minimum character count; additional rules can be added here as the well-known
- * schema (`custom_recovery_passphrase_settings`) grows.
+ * Server-driven settings for a user-chosen recovery passphrase, advertised under the well-known
+ * `custom_recovery_passphrase` key. Today the only rule is a minimum character count; additional
+ * settings can be added here as the schema grows.
  */
-data class CustomRecoveryPassphraseRequirements(
+data class CustomRecoveryPassphrase(
     val minCharacterCount: Int,
 ) {
     /** True when [input] meets every active rule. */

libraries/wellknown/api/src/main/kotlin/io/element/android/libraries/wellknown/api/ElementWellKnown.kt

@@ -15,5 +15,5 @@ data class ElementWellKnown(
     val brandColor: String?,
     val notificationSound: String?,
     val identityProviderAppScheme: String?,
-    val customRecoveryPassphraseRequirements: CustomRecoveryPassphraseRequirements?,
+    val customRecoveryPassphrase: CustomRecoveryPassphrase?,
 )