fix: IBC2 contract timeout

[jawoznia]

The IBC2 contract has hardcoded timeout as a workaround. It is done so, because the value returned by the env.block.time exceeds the maximum value expected by ibc-go which fails the execution of SendMsg in wasmd tests.

[kulikthebird]

Two PRs:

• fix: Remove the workaround #2449
• fix: Use seconds instead of nanoseconds for IBCv2 msg wasmd#2214