Harden all endowments

[rekmarks]

To the greatest extent possible, endowment made available to a snap should be hardened via SES's harden() function. This is to preclude the existence of sandbox escapes by e.g. walking properties to obtain a reference to the root realm globalThis.

This effort is complicated by the existence of endowments that may depend on mutable properties, for example the wallet provider object.

For all of the endowments we pass to snaps, we should:

1. Attempt to harden the endowment by passing it to harden().
2. If that doesn't work, ensure that its prototype has been passed to harden(), and take whatever other measures may be necessary to close unsanctioned communications channels with the root realm.

[rekmarks]

Hey team! Please add your planning poker estimate with Zenhub @david0xd @FrederikBolding @GuillaumeRx @hmalik88 @Mrtenz @ritave

[kenhkan]

Note from standup: This should be done prior to any external audits. Date to be determined.

[david0xd]

It is found that the Jest test framework does not work with SES. That makes impossible to test code that includes SES functions such as harden({...}). Replacement of the test framework is needed in the snaps-execution-environments package in order to continue work on this task properly.

Research of the potential test framework that can be used with SES is followed up in another ticket here: #1003

[kenhkan]

Additional work in this epic to be defined after initial investigation in https://app.zenhub.com/workspaces/snaps-platform-615b3a7c08d2b20015eb6c4e/issues/metamask/snaps-monorepo/1003