fix: Ensure uniqueness of public properties are compile time

[pmdartus]

Details

This PR makes compilation fail when a component defines multiple @api public properties with the same name. Currently, the compiler discards the redundant property definition and only keep the last one.

Example of failing code:

import { api } from 'engine';
export default class Text {
	@api foo = 1;
	@api foo = 2;
 // ^ Duplicate @api property "foo".
}

Does this PR introduce a breaking change?

• Yes
• No

[salesforce-best-lwc-internal]

Benchmark results

Base commit: 948fbb9 | Target commit: d231f80

lwc-engine-benchmark

table-append-1k	metric	base(948fbb9)	target(d231f80)	trend
benchmark-table/append/1k	duration	142.80 (± 3.90 ms)	144.00 (± 4.10 ms)	-0.84% 👌

table-clear-1k	metric	base(948fbb9)	target(d231f80)	trend
benchmark-table/clear/1k	duration	11.80 (± 0.60 ms)	12.10 (± 0.50 ms)	-2.54% 👌

table-create-10k	metric	base(948fbb9)	target(d231f80)	trend
benchmark-table/create/10k	duration	838.70 (± 8.00 ms)	842.20 (± 6.90 ms)	-0.42% 👎

table-create-1k	metric	base(948fbb9)	target(d231f80)	trend
benchmark-table/create/1k	duration	101.00 (± 2.30 ms)	102.95 (± 1.85 ms)	-1.93% 👎

table-update-10th-1k	metric	base(948fbb9)	target(d231f80)	trend
benchmark-table/update-10th/1k	duration	87.70 (± 4.50 ms)	91.70 (± 5.30 ms)	-4.56% 👌

tablecmp-append-1k	metric	base(948fbb9)	target(d231f80)	trend
benchmark-table-component/append/1k	duration	242.10 (± 4.90 ms)	242.10 (± 5.80 ms)	0.00% 👌

tablecmp-clear-1k	metric	base(948fbb9)	target(d231f80)	trend
benchmark-table/clear/1k	duration	30.80 (± 1.10 ms)	30.70 (± 1.20 ms)	0.32% 👌

tablecmp-create-10k	metric	base(948fbb9)	target(d231f80)	trend
benchmark-table-component/create/10k	duration	1680.80 (± 12.20 ms)	1691.30 (± 8.60 ms)	-0.62% 👎

tablecmp-create-1k	metric	base(948fbb9)	target(d231f80)	trend
benchmark-table-component/create/1k	duration	186.70 (± 4.30 ms)	188.40 (± 3.40 ms)	-0.91% 👌

tablecmp-update-10th-1k	metric	base(948fbb9)	target(d231f80)	trend
benchmark-table-component/update-10th/1k	duration	73.30 (± 4.50 ms)	74.20 (± 3.80 ms)	-1.23% 👌

[diervo]

@pmdartus O(n^2) #pieroperf :)