Add guards to make sure teh provider is initialized when required · curvefi/curve-js@85dab05

The following actions uses node12 which is deprecated and will be forced to run on node16: actions/checkout@v2, actions/setup-node@v2. For more info: https://github.blog/changelog/2023-06-13-github-actions-all-actions-will-run-on-node16-instead-of-node12-by-default/

The following actions use a deprecated Node.js version and will be forced to run on node20: actions/checkout@v2, actions/setup-node@v2. For more info: https://github.blog/changelog/2024-03-07-github-actions-all-actions-will-run-on-node20-instead-of-node16-by-default/

'registry_exchange_deprecated' is assigned a value but never used

'router_deprecated' is assigned a value but never used

'iearnSCurveRewardsABI' is defined but never used

'paaveRewardsabi' is defined but never used