update Agent.__init__ to remove deprecation warning

[quaquel]

As discussed briefly in the last developer meeting, this PR removes the deprecation warning from Agent.__init__ regarding unique_id. The main reason for removing it here is that it is the only way to ensure proper behavior of python's super. This in turn is relevant for a range of discussions (movements, HasObservable, some geo stuff).

It is agreed that in the last 2.X release, to come up with the first stable version of MESA 3, we will explicitly include a deprecation warning regarding unique_id.

References:

• track unique_id automatically #2260
• Migration guide

# Old
agent = MyAgent(self.next_id(), self, ...)

# New
agent = MyAgent(self, ...)

[github-actions]

Performance benchmarks:

Model	Size	Init time [95% CI]	Run time [95% CI]
BoltzmannWealth	small	🔴 +4.0% [+3.1%, +4.8%]	🔵 -0.5% [-0.7%, -0.4%]
BoltzmannWealth	large	🔵 +2.8% [+2.5%, +3.2%]	🔵 +1.6% [+0.6%, +2.7%]
Schelling	small	🔵 -1.2% [-1.6%, -0.8%]	🔵 +1.1% [+0.9%, +1.4%]
Schelling	large	🔵 -1.4% [-2.2%, -0.6%]	🔵 -2.6% [-5.4%, +1.0%]
WolfSheep	small	🔵 +1.6% [+1.2%, +2.1%]	🔵 +0.9% [-0.1%, +1.8%]
WolfSheep	large	🔵 +0.6% [-1.0%, +2.1%]	🔵 -3.2% [-5.7%, -0.3%]
BoidFlockers	small	🔵 +0.9% [+0.5%, +1.2%]	🔵 +0.8% [+0.0%, +1.6%]
BoidFlockers	large	🔵 +0.2% [-0.4%, +0.8%]	🔵 -1.1% [-1.6%, -0.5%]

[github-actions]

Performance benchmarks:

Model	Size	Init time [95% CI]	Run time [95% CI]
BoltzmannWealth	small	🔵 +3.6% [+2.6%, +4.4%]	🔵 -0.8% [-0.9%, -0.7%]
BoltzmannWealth	large	🔵 +1.8% [+1.3%, +2.2%]	🔵 +1.6% [+0.8%, +2.3%]
Schelling	small	🔵 -1.4% [-1.8%, -0.9%]	🔵 -0.6% [-0.8%, -0.4%]
Schelling	large	🔵 -1.1% [-1.6%, -0.6%]	🔵 +1.9% [+0.4%, +3.2%]
WolfSheep	small	🔵 +1.2% [+1.0%, +1.4%]	🔵 -0.4% [-0.6%, -0.2%]
WolfSheep	large	🔵 +1.9% [+1.2%, +2.6%]	🔵 +2.2% [+1.0%, +3.7%]
BoidFlockers	small	🔵 +2.6% [+2.3%, +3.0%]	🔵 +0.4% [-0.2%, +1.0%]
BoidFlockers	large	🔵 +1.7% [+1.2%, +2.1%]	🔵 -0.7% [-1.7%, +0.2%]