Polished agents and skills collection

[ea-rus]

Changed way of using skills and agents collections:
Instead of passing required objects to constructor - use parent collection to get them.

Fix: mindsdb/mindsdb#9561

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
mindsdb_sdk
agents.py	207	52	75%	33, 101, 104, 112, 120, 128, 136, 146, 149, 153, 155, 157, 159, 161, 163, 225, 238, 242–257, 269, 278–282, 289–290, 326, 338–339, 380, 429–430, 433, 440, 461–463, 467–471
databases.py	45	2	96%	109, 137
handlers.py	39	1	97%	77
jobs.py	97	7	93%	41, 53, 81, 85, 147–150
knowledge_bases.py	126	15	88%	58–61, 151, 155–162, 167–171, 250–253, 322, 339
ml_engines.py	42	3	93%	94, 126, 128
models.py	210	19	91%	109, 140–141, 222, 231, 233, 303, 339, 348, 372, 397, 491, 499, 518, 534, 542, 567, 571, 584
projects.py	64	1	98%	160
query.py	13	1	92%	14
skills.py	53	3	94%	43, 45, 49
tables.py	130	15	88%	140–142, 145, 165, 192, 203–204, 209, 224, 227, 321, 342–347, 356, 376
views.py	37	2	95%	105, 138
mindsdb_sdk/connectors
rest_api.py	224	42	81%	19–29, 35–36, 51, 54–55, 75–77, 98, 101, 108–111, 144–152, 173–174, 209–212, 226–227, 281–286
mindsdb_sdk/utils
mind.py	37	37	0%	1–102
openai.py	85	30	65%	37–40, 83–85, 107, 148–158, 215–216, 234–240, 258–276
table_schema.py	21	21	0%	1–54
TOTAL	1517	251	83%

Tests	Skipped	Failures	Errors	Time
23	0 💤	0 ❌	0 🔥	9.821s ⏱️

[dusvyat]

Let's fix the conflict, otherwise looks good to me