Document test failed when using memdb

[JOOHOJANG]

Description:
I found this TC fails when using memdb, but it passes when using mongoDB. (main branch)
CI cannot detect it because its using mongoDB when testing.

--- FAIL: TestDocumentWithProjects (0.65s)
    --- FAIL: TestDocumentWithProjects/includeSnapshot_test (0.01s)
panic: runtime error: index out of range [0] with length 0 [recovered]
        panic: runtime error: index out of range [0] with length 0

goroutine 4213 [running]:
testing.tRunner.func1.2({0x101ec9e00, 0xc002597f50})
        /opt/homebrew/Cellar/go/1.23.0/libexec/src/testing/testing.go:1632 +0x2c4
testing.tRunner.func1()
        /opt/homebrew/Cellar/go/1.23.0/libexec/src/testing/testing.go:1635 +0x47c
panic({0x101ec9e00?, 0xc002597f50?})
        /opt/homebrew/Cellar/go/1.23.0/libexec/src/runtime/panic.go:785 +0x124
github.com/yorkie-team/yorkie/test/integration.TestDocumentWithProjects.func3(0xc0025a6340)
        /Users/user/Documents/yorkie/test/integration/document_test.go:828 +0x3b8
testing.tRunner(0xc0025a6340, 0xc003903500)
        /opt/homebrew/Cellar/go/1.23.0/libexec/src/testing/testing.go:1690 +0x188
created by testing.(*T).Run in goroutine 4062
        /opt/homebrew/Cellar/go/1.23.0/libexec/src/testing/testing.go:1743 +0x5e4
FAIL    github.com/yorkie-team/yorkie/test/integration  26.292s
FAIL
make: *** [test] Error 1

Why:

[raararaara]

When PageSize is set to 0, MongoDB returns all results. (Official Documentation)

Unlike MongoDB, memDB does not apply any specific logic to set a limit. Currently, the implementation in memDB stops iteration when len(docInfo) is greater than or equal to PageSize.

yorkie/server/backend/database/memory/database.go

Lines 1355 to 1365 in 0871fac

	var docInfos []*database.DocInfo
	for raw := iterator.Next(); raw != nil; raw = iterator.Next() {
	info := raw.(*database.DocInfo)
	if len(docInfos) >= paging.PageSize || info.ProjectID != projectID {
	break
	}
	if info.ID != paging.Offset && info.RemovedAt.IsZero() {
	docInfos = append(docInfos, info)
	}
	}

As a result, no docInfo is returned, which seems to have caused the 'index out of range' issue.