Add name to exceptions in models/index.ts

[trivikr]

Describe the bug
Add name to exceptions in models/index.ts
Refs:

• PR which added name to error add error name to error deser #92
• CodeGen CI failure chore: add name to client Errors aws/aws-sdk-js-v3#724 (comment)

To Reproduce
Run CodeGen with latest smithy-typescript having fix in #92

Expected behavior
CodeGen CI succeeds

[trivikr]

Code which adds __type to Exception in models/index.ts https://github.com/awslabs/smithy-typescript/blob/afd715a3eb49cc4565cf2e19452d09462051507f/smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/StructureGenerator.java#L160