fix: serde wasm32 target

[dudong2]

Description

The cosmwasm_std::{to_vec, from_slice} were implemented using to serde_json_wasm::{to_vec, from_slice}. If it isn't a WASM target, using those functions may cause problems.

contracts, packages/std are wasm targets and packages/derive, packages/storage have a dependency on contracts.
packages/vm is not a wasm target.

So the change in this PR is to change the part of packages/vm that uses cosmwasm_std::{to_vec, from_slice} to serde_json based.

Closes #277

Types of changes

• Bug fix (changes which fixes an issue)
• New feature (changes which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• ETC (build, ci, docs, perf, refactor, style, test)

Checklist

• I followed the contributing guidelines.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• The PR title and commits are followed conventional commit form.

[loloicci]

LGTM!