migration: Add case to test disk size

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XXX-300490 - VM live migration with copy storage - migrate a disk to an equal or larger disk size

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Depend on: https://github.com/avocado-framework/avocado-vt/pull/3889

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Test result:

(1/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_raw.src_disk_raw.non_p2p: STARTED (1/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_raw.src_disk_raw.non_p2p: PASS (226.76 s) (2/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_raw.src_disk_block.non_p2p: STARTED (2/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_raw.src_disk_block.non_p2p: PASS (536.98 s) (3/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_block.src_disk_raw.non_p2p: STARTED (3/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_block.src_disk_raw.non_p2p: PASS (571.74 s) (4/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_block.src_disk_block.non_p2p: STARTED (4/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_block.src_disk_block.non_p2p: PASS (729.14 s)

(1/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_raw.src_disk_raw.p2p: STARTED (1/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_raw.src_disk_raw.p2p: PASS (224.58 s) (2/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_raw.src_disk_block.p2p: STARTED (2/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_raw.src_disk_block.p2p: PASS (527.51 s) (3/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_block.src_disk_raw.p2p: STARTED (3/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_block.src_disk_raw.p2p: PASS (569.97 s) (4/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_block.src_disk_block.p2p: STARTED (4/4) type_specific.io-github-autotest-libvirt.migration_with_copy_storage.target_image_larger_than_source.target_disk_block.src_disk_block.p2p: PASS (715.17 s)