Fix bug in Bytes.lastIndexOf when array is empty and position is not 2²⁵⁶-1

[Amxx]

Fix bug introduced in #5252 (v5.2)

Bug description

If the buffer is empty and if pos is not type(uint256).max

• in the computation of Math.min(pos, length - 1) + 1, length-1 overflow and return 2²⁵⁶-1.
• taking the min between pos and that will return something that is NOT 2²⁵⁶-1.
• adding 1 to it will NOT return 0.
• the loop will start at a non-0 index, and try to access data when the buffer is actually empty.

This will return unpredictable results, if s can be found after the buffer. For example, if the memory after the is clean (zero) and you do lastIndexOf('0x', '0x00', 17) ... it will return 17 instead of the expected 2²⁵⁶-1 (not found)

PR Checklist

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Latest commit: cfbb2e6

The changes in this PR will be included in the next version bump.

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Name	Type
openzeppelin-solidity	Patch

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