[BUG]: npx drizzle-kit introspect --> drizzle-kit/bin.cjs:21699 TypeError: Cannot read properties of undefined (reading 'toLowerCase')

### What version of `drizzle-orm` are you using?

0.31.0

### What version of `drizzle-kit` are you using?

0.22.1

### Describe the Bug

When using "npx drizzle-kit introspect" the command runs, but does not complete. Throws the following error.

```sh
$ npx drizzle-kit introspect
drizzle-kit: v0.22.1
drizzle-orm: v0.31.0

No config path provided, using default path
Reading config file '...PATH_TO_PROJECT_ROOT/drizzle.config.ts'
Pulling from ['public'] list of schemas

Using 'postgres' driver for database querying
[✓] 18 tables fetched
[⢿] 89 columns fetching
[✓] 9 enums fetched
[⢿] 0 indexes fetching
[⢿] 5 foreign keys fetching

.../node_modules/drizzle-kit/bin.cjs:21699
const onUpdate = fk4.update_rule.toLowerCase();
^

TypeError: Cannot read properties of undefined (reading 'toLowerCase')
at ..PATH_TO_PROJECT_ROOT/node_modules/drizzle-kit/bin.cjs:21699:48
at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

Node.js v22.1.0
```

``` Typescript
// config.drizzle.ts
import { config } from 'dotenv';
import { defineConfig } from 'drizzle-kit';
import { resolve } from 'path';

// Load environment variables from .env.local
// Next JS uses .env.local instead of .env see: https://nextjs.org/docs/basic-features/environment-variables
config({
path: [resolve(__dirname, '.env.local'), resolve(__dirname, '.env')],
});

// Drizzle-Kit Specific Configuration
export default defineConfig({
schema: './src/db/schema.ts',
out: './supabase/migrations',
dialect: 'postgresql',
dbCredentials: {
url: process.env.DATABASE_URL!,
},
});
```

---
Tried trouble shooting.
Error replicates with new project using an example schema given in the Supabase/Drizzle docs.

The example schema used:
```typesript
// dasdf
import {
pgTable,
serial,
text,
timestamp,
integer,
varchar,
boolean,
} from 'drizzle-orm/pg-core';

export const usersTable = pgTable('users_table', {
id: serial('id').primaryKey(),
name: text('name').notNull(),
age: integer('age').notNull(),
email: text('email').notNull().unique(),
});

export const postsTable = pgTable('posts_table', {
id: serial('id').primaryKey(),
title: text('title').notNull(),
content: text('content').notNull(),
userId: integer('user_id')
.notNull()
.references(() => usersTable.id, { onDelete: 'cascade' }),
createdAt: timestamp('created_at').notNull().defaultNow(),
updatedAt: timestamp('updated_at')
.notNull()
.$onUpdate(() => new Date()),
});

export type InsertUser = typeof usersTable.$inferInsert;
export type SelectUser = typeof usersTable.$inferSelect;

export type InsertPost = typeof postsTable.$inferInsert;
export type SelectPost = typeof postsTable.$inferSelect;
```

Run the following commands:
```sh
npx drizzle-kit generate
npx drizzle-kit migrate
npx drizzle-kit pull
npx drizzle-kit introspect
```
Getting same error in shell:
```sh
$ npx drizzle-kit introspect
drizzle-kit: v0.22.1
drizzle-orm: v0.31.0

No config path provided, using default path
Reading config file '..PATH_TO_PROJECT_ROOT/drizzle.config.ts'
Pulling from ['public'] list of schemas

Using 'postgres' driver for database querying
[✓] 2 tables fetched
[⣽] 6 columns fetching
[✓] 9 enums fetched
[⣽] 0 indexes fetching
[⣽] 3 foreign keys fetching
..PATH_TO_PROJECT_ROOT/node_modules/drizzle-kit/bin.cjs:21699
const onUpdate = fk4.update_rule.toLowerCase();
^

TypeError: Cannot read properties of undefined (reading 'toLowerCase')
at ..PATH_TO_PROJECT_ROOT/node_modules/drizzle-kit/bin.cjs:21699:48
at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

Node.js v22.1.0

```

### Expected behavior

Would expect it to complete introspection and generate the schema.ts file in the location specified in the config.drizzle.ts file.

### Environment & setup

Using Supabase and Next JS.
Taking database and contents from an existing Django projects.