Upgrade Typescript to 5.9

[sosnovsky]

Upgrading to Typescript 5.9 causes some build errors (https://flowcrypt.semaphoreci.com/jobs/fd4acffd-4b9c-4c8a-aed1-0c9864de46f3):

/home/semaphore/git/flowcrypt-browser/extension/js/common/browser/browser.ts (13,42): Type 'string | Uint8Array<ArrayBufferLike>' is not assignable to type 'BlobPart'.
  Type 'Uint8Array<ArrayBufferLike>' is not assignable to type 'BlobPart'.
    Type 'Uint8Array<ArrayBufferLike>' is not assignable to type 'ArrayBufferView<ArrayBuffer>'.
      Types of property 'buffer' are incompatible.
        Type 'ArrayBufferLike' is not assignable to type 'ArrayBuffer'.
          Type 'SharedArrayBuffer' is not assignable to type 'ArrayBuffer'.
            Types of property '[Symbol.toStringTag]' are incompatible.
              Type '"SharedArrayBuffer"' is not assignable to type '"ArrayBuffer"'.
/home/semaphore/git/flowcrypt-browser/extension/js/common/core/crypto/smime/smime-key.ts (110,47): Argument of type 'Uint8Array<ArrayBufferLike>' is not assignable to parameter of type 'string | ArrayBuffer | ByteStringBuffer | ArrayBufferView'.
  Type 'Uint8Array<ArrayBufferLike>' is missing the following properties from type 'ByteStringBuffer': data, read, isEmpty, putByte, and 30 more.
/home/semaphore/git/flowcrypt-browser/extension/js/common/core/crypto/smime/smime-key.ts (154,47): Argument of type 'Uint8Array<ArrayBufferLike>' is not assignable to parameter of type 'string | ArrayBuffer | ByteStringBuffer | ArrayBufferView'.
  Type 'Uint8Array<ArrayBufferLike>' is missing the following properties from type 'ByteStringBuffer': data, read, isEmpty, putByte, and 30 more.
/home/semaphore/git/flowcrypt-browser/extension/js/common/platform/store/encryption-key-store.ts (14,7): Type 'Buf' is not assignable to type 'ArrayBuffer'.
  The types of 'slice(...)[Symbol.toStringTag]' are incompatible between these types.
    Type '"Uint8Array"' is not assignable to type '"ArrayBuffer"'.
/home/semaphore/git/flowcrypt-browser/extension/js/common/platform/store/encryption-key-store.ts (18,5): Type 'Uint8Array<ArrayBufferLike>' is not assignable to type 'ArrayBuffer'.
  The types of 'slice(...)[Symbol.toStringTag]' are incompatible between these types.
    Type '"Uint8Array"' is not assignable to type '"ArrayBuffer"'.