modify _readClientSideDirectiveField in RelayReader to work for exec … #8365

Job	Run time
Rust Tests (ubuntu-latest)	4m 28s
Compiler output check (ubuntu-latest)	4m 26s
Build Rust Compiler (ubuntu-latest)	4m 36s
Rust Tests (macos-latest)	3m 38s
Compiler output check (macos-latest)	3m 11s
Build Rust Compiler (ubuntu-latest)	5m 38s
Rust Tests (windows-latest)	6m 38s
Build Rust Compiler (macos-latest)	4m 24s
JS Lint	59s
Build Rust Compiler (macos-latest)	3m 21s
JS Tests (Node 18.x)	1m 30s
Rust Lint	14s
Build Rust Compiler (windows-latest)	8m 21s
Flow Typecheck	38s
VSCode Extension Lint	21s
JS Tests (Node 20.x)	1m 44s
Publish to NPM	1m 30s
	55m 37s

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