added safeguard

[FaroutYLq]

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What does the code in this PR do / what does it improve?

Require that no instruction should be actually used to simulate in the last 50ms of a chunk.

Potential risk: part of the instruction (anything in the last 50ms of a chunk) will NOT be simulated and seems as missing. We don't want to have this misunderstood by PEMA.

Can you briefly describe how it works?

Manually remove instructions in the last 50ms of each chunk.

        instructions = instructions[(instructions['time'] >= start) & 
                                    (instructions['time'] < end)] # Probably need safeguard here
                                    (instructions['time'] < end-NS_NO_INSTRUCTION_BEFORE_CHUNK_END)]

Can you give a minimal working example (or illustrate with a figure)?

Please include the following if applicable:

• Add an appropriate tag to this PR
• Update the docstring(s)
• Update the documentation
• Tests to check the (new) code is working as desired.
• Does it solve one of the open issues on github?

Notes on testing

• Until the automated tests pass, please mark the PR as a draft.
• On the XENONnT fork we test with database access, on private forks there is no database access for security considerations.

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