bugfix: repro and fix for issue #4267 (reject too long principals in Principal.fromBlob and actor literals)

[crusso]

Fixes issues #4267:

• BREAKING CHANGE (Minor): values of type Principal are now constrained to contain
  at most 29 bytes, matching the IC's notion of principal (bugfix: repro and fix for issue #4267 (reject too long principals in Principal.fromBlob and actor literals) #4268).

  In particular:

  • An actor import will be statically rejected if the binary representation of the (aliased) textually encoded
    principal contains strictly more than 29 bytes.

  • Principal.fromBlob(b) will trap if b contains strictly more than 29 bytes.

  • The actor literal, actor <exp>, will trap if the binary representation of
    of the textually encoded principal <exp> contains strictly more than 29 bytes.

[github-actions]

Comparing from 7fbe013 to f70b545:
In terms of gas, 1 tests regressed, 2 tests improved and the mean change is -1.6%.
In terms of size, 5 tests regressed and the mean change is +0.0%.

[crusso]

Part of me thinks it would have been cleaner just to remove the candid length check on deserialization and rely on the IC checking principal lengths... that would avoid changing the candid spec too....

[nomeata]

LGTM