[Security Solution] Fix generation of circular types using non-circular types (#187061)

**Relates to:** https://github.com/elastic/kibana/issues/186066, https://github.com/elastic/kibana/pull/186221

## Summary

This PR fixes generated TS files for circular OpenAPI schemas when non circular (internal or external) schema is used.

## Details

https://github.com/elastic/kibana/pull/186221 added code generation support for circular schemas. Such schemas have input TS types generated which may depend on the other circular or non circular TS types. The problem appears when a circular schema uses a non circular schema. Generated code expects an input type for used schemas exist but it's not a case non circular schemas.

Let's consider a following OpenAPI spec with a self circular schema and a field referencing `NonEmptyString` schema

```yaml
...
components:
  x-codegen-enabled: true
  schemas:
    SelfCircular:
      type: object
      properties:
        circularField:
          $ref: '#/components/schemas/SelfCircular'
        stringField:
          $ref: '../model/primitives.schema.yaml#/components/schemas/NonEmptyString'
```

where a generated TS file looks like

```ts
import type { ZodTypeDef } from 'zod';
import { z } from 'zod';

import { NonEmptyString } from '../model/primitives.gen';

export interface SelfCircular {
  circularField?: SelfCircular;
  stringField?: NonEmptyString;
}
export interface SelfCircularInput {
  circularField?: SelfCircularInput;
  stringField?: NonEmptyStringInput;
}
export const SelfCircular: z.ZodType<SelfCircular, ZodTypeDef, SelfCircularInput> = z.object({
  circularField: z.lazy(() => SelfCircular).optional(),
  stringField: NonEmptyString.optional(),
});
```

You can notice the generated TS file contains usage of `NonEmptyStringInput` which doesn't exist.

**After applying the fix the generated TS file looks like**

```ts
import type { ZodTypeDef } from 'zod';
import { z } from 'zod';

import { NonEmptyString } from '../model/primitives.gen';

export interface SelfCircular {
  circularField?: SelfCircular;
  stringField?: NonEmptyString;
}
export interface SelfCircularInput {
  circularField?: SelfCircularInput;
  stringField?: NonEmptyString;
}
export const SelfCircular: z.ZodType<SelfCircular, ZodTypeDef, SelfCircularInput> = z.object({
  circularField: z.lazy(() => SelfCircular).optional(),
  stringField: NonEmptyString.optional(),
});
```

packages/kbn-openapi-generator/src/template_service/templates/ts_input_type.handlebars

@@ -3,7 +3,8 @@
 {{~/if~}}
 
 {{~#if $ref~}}
-  {{referenceName}}Input
+  {{referenceName}}
+  {{~#if (isCircularRef $ref)}}Input{{/if~}}
   {{~#if nullable}} | null {{/if~}}
 {{~/if~}}