Code Review Bench PR #14637 - Fix adjacent slot range behavior in ASM operations

[tomerqodo]

Code Review Bench PR redis#14637

Original PR Title: Fix adjacent slot range behavior in ASM operations
Original PR Description: This PR containts a few changes for ASM:

Bug fix:

• Fixes an issue in ASM when adjacent slot ranges are provided in CLUSTER MIGRATION IMPORT command (e.g. 0-10 11-100). ASM task keeps the original slot ranges as given, but later the source node reconstructs the slot ranges from the config update as a single range (e.g. 0-100). This causes asmLookupTaskBySlotRangeArray() to fail to match the task, and the source node incorrectly marks the ASM task as failed. Although the migration completes successfully, the source node performs a blocking trim operation for these keys, assuming the slot ownership changed outside of an ASM operation. With this PR, redis merges adjacent slot ranges in a slot range array to avoid this problem.

Other improvements:

• Indicates imported/migrated key count in the log once asm operation is completed.
• Use error return value instead of assert in parseSlotRangesOrReply()
• Validate slot range array that is given by cluster implementation on ASM_EVENT_IMPORT_START.

Original PR URL: redis#14637