This commit only points to the new version, making sure the module and test compiles,
but makes no logic changes to e.g. add support to new key algos/formats.

OpenPGP.js v6 drops support for platforms without native BigInts

Adding support for TS v5.

…erated key prefs

OpenPGP.js v5 does not support sha3, so we should not include it in the key prefs
until the full v6 integration in the webapps and mobile.

…ions

Also, rename `MaybeStream` to `MaybeWebStream` to help differentiate it from
`openpgpjs.MaybeStream`, which can also be a NodeStream.

…lic keys (default to `config.ignoreSEIPDv2FeatureFlag: true`)

We want to avoid generating SEIPDv2 messages until support is rolled out to other platforms,
in case e.g. some users have already imported v4 keys with SEIPDv2 feature flags.

This change affects `encryptMessage` and `generateSessionKeys` when `encryptionKeys` are given
(rather than `passwords`).

Addressing issue in Firefox's WebCrypto with x25519

To test latest browser versions

No longer used since removal of legacy message decryption support

To avoid issues when using e.g. Babel/SWC/Vite in the web-app tests
(https://typescript-eslint.io/blog/consistent-type-imports-and-exports-why-and-how#isolated-module-transpilation)