[broker] Revert PR 6404:"Consumer received duplicated deplayed messages upon restart"

[dao-jun]

Motivation

#6404 is to fix duplicated messages after broker restart(Especially for delayed messages).
However, since we introduced #19035, it has to some extent solved this problem,
but this logic still exists, in some cases, it may lead to more serious duplication problems.

#6404 wants to skip read entries which are to replay. Say, if entry [1] is
a delay message, and the current readPosition is [1], it can move the readPosition to [2] to avoid normal read operations read the entry to resolve message duplication.

However, it may have a chance to move the Cursor#readPosition backward:

	replay read	normal read
step 1	read entry 1	read entries [1, 10]
step 2	the readPosition equals 1
step 3		read [1, 10] complete
step 4		update readPosition to 11
step 5	update readPosition to 2

Since it moved the readPosition backward to 2, so even though broker read [1, 10] from BK and dispatched them to client, but it will also read [2, 11] from BK then dispatch in the next reading, [2, 10] will be duplicated.

Modifications

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Matching PR in forked repository

PR in forked repository:

[lhotari]

but this logic still exists, in some cases, it may lead to more serious duplication problems.

please share more details. Do you have a chance to add a test case for this PR?

[dao-jun]

@lhotari I updated the description