Several spells' sub-spells have 1 level, instead of same amount as the main spell

[bu3ny]

There are a bunch of sub-spells which are always on level 1, regardless of the main spell they belong to.

This is an issue because:

1. ALT-clicking the sub-spell always says it's level 1, regardless of which level the spell actually is
2. illusions created of the hero while their sub-spell is active makes the illus have the spell on level 1, instead of the level the hero actually has it
3. The spells cannot be leveled up while the sub-spell is active


Affected spells are:
* Ice Blast
* Tether
* Nightmare
* Telekinesis
* Song of the Siren

This should be easy to fix:
* Give the sub-spells the same amount of levels as the main spell, instead of 1 level (needs 1 number change on the abilities in the npc_abilities.txt file)
* Add codes to the spell which sets the level of the sub-spell equal to the main spell (can be just copied from other sub-spells which already do this, like Phoenix' Timbersaw's and Kotl's sub-spells, or Shadowraze or Test of Faith, etc.)

[The_Zett]

Dawnbreaker’s "Solar Guardian Land" spell has the same issue, so do "Return Astral Spirit" (and technically "Move Astral Spirit") and Telekinesis (shard).

Additionally, the sub-spells for Freezing Field, Converge, Sharpshooter, Illuminate, Illuminate (Spirit Form), Sunray, Rolling Thunder, Onslaught, Snowball, Chakram & Chakram (Aghs) cannot be leveled up while using them, which is inconsistent with other sub-spells that can be leveled up while using their main component (e.g. Alch’s Unstable Concoction or X marks the Spot).