[6.3]Check ASSETCATALOG_COMPILER_GENERATE_ASSET_SYMBOLS and STRING_CATALOG_GENERATE_SYMBOLS build settings before moving compilation of Asset Catalog and String Catalog into Souece phase

[Tantalum73]

Same changes as #1174, but targetting release/6.3.

Asset Catalogs and String Catalogs can generate code to allow for easy access to colors, images, and strings. Because of this, their compilation needs to happen in the Sources build phase. When configured to be in a Resources phase, we move them into Sources automatically.
#705 refactored the code to generalize the idea.

By accident, that changed a behavior where build settings to generate these symbols were not taken into account. Before #705, Asset Catalogs were only moved when ASSETCATALOG_COMPILER_GENERATE_ASSET_SYMBOLS was YES. After #705, the move happened unconditionally.

This PR fixes that by only moving Catalogs to the Sources phase when they actually produce sources to compile.

[owenv]

Explanation:
See above

Scope:
Projects with ASSETCATALOG_COMPILER_GENERATE_ASSET_SYMBOLS=NO

Original PRs:
#1174

Risk:
Low-to-Moderate. Affects asset catalog and xcstrings compilation ordering, but in a targeted manner. Changes are covered by tests

Testing:
Added unit tests

Reviewers:
@owenv

[owenv]

@swift-ci test

[owenv]

Tests need a small adjustment for the 6.3 branch:

build/Tests/SWBTaskConstructionTests/XCStringsSymbolGenTests.swift:1124:60: error: extra argument 'hostOS' in call
13:39:12  1122 | 
13:39:12  1123 |         let core = try await getCore()
13:39:12  1124 |         let xcstringsTool = MockXCStringsTool(hostOS: core.hostOperatingSystem, relativeOutputFilePaths: [ 

[owenv]

@swift-ci test