isisd: fix change flex-algorithm number from uint32 to uint8 (backport #17250)

[mergify]

The algorithm number is encoded on 8 bits and does not require an unsigned 32 bit value to store the value.

Fixes: cc4926c ("isisd,yang: add algorithm-prefix-sid configuration tree")

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This is an automatic backport of pull request #17250 done by Mergify.

[mergify]

Cherry-pick of 8e861a7 has failed:

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Changes to be committed:
	modified:   yang/frr-isisd.yang

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   isisd/isis_cli.c
	both modified:   isisd/isis_nb_config.c

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