Harden custom endowments

[david0xd]

Fixes: #1017

This PR will add implementation for hardening of the custom endowments: ethereum and snap.
Final result should ensure that these endowments cannot be changed within their prototype chain.
Hardening is done by using harden function provided by SES.

There are minor adaptations to the Proxy implementations of these endowments in order to prevent these objects leaking their prototype chain up to the StreamProvider and further. This is required because the harden function will reach the parts of the StreamProvider and further, then freeze it. Deep freeze of the Stream functionalities would prevent it from working properly. This way, the hardening is done and the prototype chain is safe.

[codecov-commenter]

Codecov Report

Merging #1172 (25afade) into main (a9abb8b) will increase coverage by 0.02%.
The diff coverage is 100.00%.

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@@            Coverage Diff             @@
##             main    #1172      +/-   ##
==========================================
+ Coverage   94.09%   94.12%   +0.02%     
==========================================
  Files         140      140              
  Lines        5773     5800      +27     
  Branches      859      863       +4     
==========================================
+ Hits         5432     5459      +27     
  Misses        341      341              

Impacted Files	Coverage Δ
...cution-environments/src/common/BaseSnapExecutor.ts	91.24% <100.00%> (-0.23%)	⬇️
...s/snaps-execution-environments/src/common/utils.ts	100.00% <100.00%> (ø)

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[naugtur]

Looks good overall, I'll give it another pass.

[naugtur]

Looks done