Fix: update tranches not performing any updates

[shark0der]

Context

Fixes #299

When the pool is new, the function was always skipping the updates, never updating any value. Because of this early exit the function was never updating anything.

Changes proposed in this pull request

The new implementation will stil exit early without updating anything if a forced update was not requested (updateUntilCurrentTimestamp = true). A force update should be requested if the function calling updateTranches changes the share supply. If the share supply is not being changed - we should be fine skipping the update i.e. avoid any writes.

I'm not entirely sure there aren't any edge cases that I didn't account for. Please review carefully.

Test plan

No tests present for staking at the moment.

Checklist

• Rebased the base branch
• Attached corresponding Github issue
• Prefixed the name with the type of change (i.e. feat, chore, test)
• Performed a self-review of my own code
• Followed the style guidelines of this project
• Made corresponding changes to the documentation
• Didn't generate new warnings
• Didn't generate failures on existing tests
• Added tests that prove my fix is effective or that my feature works

Review

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• 🚀 = Feedback

[0xdewy]

Seems good to me 🚀