Update G2 trusted setup length to 65

[hwwhww]

Thank @pawanjay176 for raising this issue.

As @dankrad pointed out:

• The full setup will have 65 so that it can provide multiproofs up to size 64 field elements (2kB)
• It is okay to use 65 G2 elements for both mainnet and minimal presets.

This PR:

• Add KZG_SETUP_G2_LENGTH := 65
• Update the length of KZG_SETUP_G2 to Vector[G2Point, KZG_SETUP_G2_LENGTH]
• Update testing trusted setups accordingly

nitpicking: it looks a little weird that there is no KZG_SETUP_G1_LENGTH := 4096... but it's simpler just to use FIELD_ELEMENTS_PER_BLOB.

[asn-d6]

Danny beat me to it, but LGTM.