Fix multi-select option removal crashing when records contain removed values (#18871)

## Summary

- Fixes a bug where removing an option from a MULTI_SELECT field fails
with `invalid input value for enum` when existing records contain the
removed value alongside surviving values.
- The root cause was the `ELSE` branch in `updateArrayEnum` which tried
to cast removed enum values (e.g. `DISTRIBUTOR`) to the new enum type
that no longer includes them.
- The fix replaces the `ELSE` cast with a NULL-producing implicit CASE
default and uses `array_agg(...) FILTER (WHERE mapped_value IS NOT
NULL)` to silently strip removed values from existing arrays.

### Before (bug)
```sql
-- ELSE branch tries to cast removed value to new enum → crash
CASE unnest_value::text
  WHEN 'IMPL' THEN 'IMPL'::new_enum
  WHEN 'APP' THEN 'APP'::new_enum
  ELSE unnest_value::text::new_enum  -- 'DISTRIBUTOR' fails here
END
```

### After (fix)
```sql
-- No ELSE: removed values produce NULL, filtered out by array_agg
SELECT array_agg(mapped_value) FILTER (WHERE mapped_value IS NOT NULL)
FROM (
  SELECT CASE unnest_value::text
    WHEN 'IMPL' THEN 'IMPL'::new_enum
    WHEN 'APP' THEN 'APP'::new_enum
  END AS mapped_value
  FROM unnest(old_column) AS unnest_value
) enum_mapping
```

packages/twenty-server/src/engine/twenty-orm/workspace-schema-manager/services/workspace-schema-enum-manager.service.ts

@@ -327,7 +327,6 @@ export class WorkspaceSchemaEnumManagerService {
           escapedTable,
           escapedOldColumn,
           escapedNewColumn,
-          escapedNewEnumType,
           escapedOldEnumType: `${escapedSchema}.${escapeIdentifier(oldEnumTypeName)}`,
           caseStatements,
           mappedValuesCondition,
@@ -349,7 +348,6 @@ export class WorkspaceSchemaEnumManagerService {
     escapedOldColumn,
     escapedSchema,
     escapedTable,
-    escapedNewEnumType,
     escapedOldEnumType,
     caseStatements,
     mappedValuesCondition,
@@ -358,7 +356,6 @@ export class WorkspaceSchemaEnumManagerService {
     escapedTable: string;
     escapedOldColumn: string;
     escapedNewColumn: string;
-    escapedNewEnumType: string;
     escapedOldEnumType: string;
     caseStatements: string;
     mappedValuesCondition: string;
@@ -366,13 +363,14 @@ export class WorkspaceSchemaEnumManagerService {
     return `
           UPDATE ${escapedSchema}.${escapedTable}
           SET ${escapedNewColumn} = (
-            SELECT array_agg(
-              CASE unnest_value::text
-                ${caseStatements}
-                ELSE unnest_value::text::${escapedNewEnumType}
-              END
-            )
-            FROM unnest(${escapedOldColumn}) AS unnest_value
+            SELECT array_agg(mapped_value) FILTER (WHERE mapped_value IS NOT NULL)
+            FROM (
+              SELECT
+                CASE unnest_value::text
+                  ${caseStatements}
+                END AS mapped_value
+              FROM unnest(${escapedOldColumn}) AS unnest_value
+            ) enum_mapping
           )
           WHERE ${escapedOldColumn} IS NOT NULL
             AND ${escapedOldColumn} && ARRAY[${mappedValuesCondition}]::${escapedOldEnumType}[]`;