Bump Oasis Core to 26.0

[kostko]

No description provided.

[netlify]

✅ Deploy Preview for oasisprotocol-oasis-sdk canceled.

Name	Link
🔨 Latest commit	59ad3e9
🔍 Latest deploy log	https://app.netlify.com/projects/oasisprotocol-oasis-sdk/deploys/69b3b29debdb9800088f3a05

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 51.27%. Comparing base (3fd58e3) to head (59ad3e9).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
runtime-sdk/modules/evm/src/types.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2431      +/-   ##
==========================================
+ Coverage   48.59%   51.27%   +2.67%     
==========================================
  Files         225      237      +12     
  Lines       16128    17039     +911     
==========================================
+ Hits         7838     8736     +898     
- Misses       8230     8243      +13     
  Partials       60       60              

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