Do not throw when an ESM script has attribute data but no schema

[mvaligursky]

Description

ScriptComponent#initializeAttributes warns that a schema is required for the data to be instantiated, then falls straight through and dereferences it anyway:

const schema = this.system.app.scripts?.getSchema(name);
if (!schema) {
    Debug.warnOnce(`No schema exists for the script '${name}'. ...`);
}

assignAttributesToScript(this.system.app, schema.attributes, data, script);

So creating a Script class with attribute data but no registered schema throws TypeError: Cannot read properties of undefined (reading 'attributes') out of ScriptComponent#create, rather than just warning:

class MyScript extends Script {
    static scriptName = 'myScript';
}
entity.script.create(MyScript, { attributes: { speed: 42 } });   // throws

Return after the warning, which is what the message already says happens. Note the Debug call is stripped from release builds while the dereference is not, so the throw is there in both.

Found while writing tests for #9203, unrelated to the clone path.

Testing

One test in test/framework/components/script/component.test.mjs, fails on main: creating a Script with attribute data and no schema warns, does not throw, and leaves the script instance usable with no attributes assigned.

Checklist

• I have read the contributing guidelines
• My code follows the project's coding standards
• This PR focuses on a single change

🤖 Generated with Claude Code

[github-actions]

Build size report

This PR changes the size of the minified bundles.

Bundle	Minified	Gzip	Brotli
playcanvas.min.js	2372.2 KB (+0.0 KB, +0.00%)	609.6 KB (+0.0 KB, +0.00%)	473.4 KB (−0.0 KB, −0.01%)
playcanvas.min.mjs	2369.6 KB (+0.0 KB, +0.00%)	608.5 KB (+0.0 KB, +0.00%)	472.7 KB (−0.1 KB, −0.03%)

[mvaligursky]

Automated PR review by Codex (GPT-5).

No actionable issues found.

The early return matches the existing warning contract and is required outside debug builds as well, where the Debug call is stripped but the schema dereference would otherwise remain. It leaves the script instance usable, avoids fabricating an attribute layout without a schema, and preserves the stored raw data should initialization be retried after a schema is supplied.

Local verification on the exact head: the full focused ScriptComponent suite passed (89 tests), ESLint passed for both changed files, and git diff --check passed. All current GitHub checks are green.