Remove Signal ComponentEffect.format usage

[HerbertsVaadin]

Solves #4661

• Replaced ComponentEffect.format with its equivalent, since the format method has been removed.
• Verified all other the examples still work
• Added link to server push documentation where it was mentioned.

[github-actions]

AI Language Review

In the file "Manage UI State With Signals":

1. The section "Simple Counter Example" provides two code snippets that demonstrate similar functionality. The updated example uses the ComponentEffect.effect without the intermediate helper function ComponentEffect.format. This change improves clarity by directly showing the effect implementation.

2. There's a reference to enabling push in the "Text Field Example" section, which uses a special syntax (<<{articles}/flow/advanced/server-push#push.configuration.enabling,enable push>>). This change makes the instruction clear and actionable.

Overall, the changes enhance the existing examples and documentation by clarifying implementation details, such as showing direct code instead of abstracted helper functions. No issues require improvement in the modified sections.

[CLAassistant]

All committers have signed the CLA.

[mshabarov]

@HerbertsVaadin please sign the new CLA.

[HerbertsVaadin]

@mshabarov thanks, done.
What's the process from this point usually, once approved? Am I expected to merge myself, or await someone else to do it?