fix(typescript): alias imported types in (de)serialization schemas

This fixes an issue where a type imported in a (de)serialization schema has
the same name as the exported schema, causing build errors.

Without this fix, we'd have schemas generated looking like so:

```ts
/**
 * This file was auto-generated by Fern from our API Definition.
 */

import * as serializers from "../../../index";
import * as Engine from "../../../../api/index";
import * as core from "../../../../core";
import { SecurityFinding } from "../../ocsf/resources/v110/resources/securityfinding/resources/classes/types/SecurityFinding";

export const SecurityFinding: core.serialization.ObjectSchema<serializers.SecurityFinding.Raw, Engine.SecurityFinding> = SecurityFinding;

export declare namespace SecurityFinding {
    type Raw = SecurityFinding.Raw;
}
```

The imported `SecurityFinding` type shares the same name as the
serialization schema, which then causes build errors that are hard and
awkward to fix in post processing of the generated source code.

After this fix, the generated code looks like so:

```ts
/**
 * This file was auto-generated by Fern from our API Definition.
 */

import * as serializers from "../../../index";
import * as Engine from "../../../../api/index";
import * as core from "../../../../core";
import { SecurityFinding as SecurityFindingType } from "../../ocsf/resources/v110/resources/securityfinding/resources/classes/types/SecurityFinding";

export const SecurityFinding: core.serialization.ObjectSchema<serializers.SecurityFinding.Raw, Engine.SecurityFinding> = SecurityFindingType;

export declare namespace SecurityFinding {
    type Raw = SecurityFindingType.Raw;
}
```

The added `Type` suffix ensures the names do not conflict, solving any build
issues that would otherwise arise.

generators/typescript/sdk/generator/src/contexts/type-schema/TypeSchemaContextImpl.ts

@@ -146,7 +146,7 @@ export class TypeSchemaContextImpl implements TypeSchemaContext {
                       useDynamicImport: false,
                       namespaceImport: "serializers"
                   }
-                : { type: "direct" },
+                : { type: "direct", alias: `${typeName.name.originalName}Type` },
             // TODO this should not be hardcoded here
             subImport: ["Raw"],
             importsManager: this.importsManager,
@@ -175,7 +175,7 @@ export class TypeSchemaContextImpl implements TypeSchemaContext {
                         return { type: "fromRoot", useDynamicImport: false, namespaceImport: "serializers" };
                     } else if (isGeneratingSchema) {
                         // Return default import strategy or another strategy based on your logic
-                        return { type: "direct" };
+                        return { type: "direct", alias: `${typeName.name.originalName}Type` };
                     } else {
                         // We don't really know when or if this case is actually used
                         return getSchemaImportStrategy({ useDynamicImport: false });