fix(smithy-client): add prototype chain fallback for service exception

[siddsriv]

Description of changes:
adds prototype chain check for the isInstance method for ServiceException

Testing

✓ src/client.spec.ts (7)
 ✓ src/command.spec.ts (2)
 ✓ src/create-aggregated-client.spec.ts (4)
 ✓ src/date-utils.spec.ts (155)
 ↓ src/emitWarningIfUnsupportedVersion.spec.ts (7) [skipped]
 ✓ src/exceptions.spec.ts (16)
 ✓ src/get-value-from-text-node.spec.ts (3)
 ✓ src/is-serializable-header-value.spec.ts (4)
 ✓ src/lazy-json.spec.ts (7)
 ✓ src/object-mapping.spec.ts (8)
 ✓ src/parse-utils.spec.ts (430)
 ✓ src/quote-header.spec.ts (4)
 ✓ src/ser-utils.spec.ts (4)
 ✓ src/serde-json.spec.ts (3)
 ✓ src/split-every.spec.ts (5)
 ✓ src/split-header.spec.ts (2)

 Test Files  15 passed | 1 skipped (16)
      Tests  654 passed | 7 skipped (661)
   Start at  18:40:22
   Duration  1.39s (transform 836ms, setup 0ms, collect 1.71s, tests 353ms, environment 4ms, prepare 1.94s)

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[cpyle0819]

Thanks for the quick turnaround. Looks good.