[Release-1.28] - rke2-server creates improper etcd member name

[brandond]

Backport fix for rke2-server creates improper etcd member name

• rke2-server creates improper etcd member name #5482

[VestigeJ]

Reproduced and steps over here #5482 (comment)

Validation:

$ get_etcd

+------------------+---------+----------------------------------------------+----------------------------+----------------------------+------------+
|        ID        | STATUS  |                     NAME                     |         PEER ADDRS         |        CLIENT ADDRS        | IS LEARNER |
+------------------+---------+----------------------------------------------+----------------------------+----------------------------+------------+
| 4fb912b6041ccf97 | started | justjustnewnew-pool1-9495f497-pkt4l-786939d7 |  https://1.1.1.13:2380      |  https://1.1.1.13:2379     |      false |
| 531cf91daf3687be | started | justjustnewnew-pool1-9495f497-g7lvj-7c6a7e3f | https://1.1.1.129:2380     | https://1.1.1.129:2379     |      false |
| fc80248a8f44dfad | started | justjustnewnew-pool1-9495f497-dnpnf-71cc3a00 |  https://1.1.1.94:2380      |  https://1.1.1.94:2379     |      false |
+------------------+---------+----------------------------------------------+----------------------------+----------------------------+------------+

$ rke2 -v

rke2 version v1.28.8-rc1+rke2r1 (42cab2f61939504cb17073e47deaea0b29fe2c1b)
go version go1.21.8 X:boringcrypto