…eType`

**Summary**
This commit modifies `ScriptTypeParser::parseTypeFromExpr` so that
string literal type annotations are resolved using
`Resolver::resolveType`. At present, they are parsed in
`parseBaseTypeName`, which inadvertently allows any key from
`string_to_type_lut` to be used as a string literal type annotation.

**Test Plan**
Existing unit tests (most notably
`TestClassType.test_self_referential_method` which tests the main
feature, self-referential class type annotations, that make use of
string literal type annotations).

**Fixes**
This commit fixes #47570.

[ghstack-poisoned]

…ver::resolveType`"

**Summary**
This commit modifies `ScriptTypeParser::parseTypeFromExpr` so that
string literal type annotations are resolved using
`Resolver::resolveType`. At present, they are parsed in
`parseBaseTypeName`, which inadvertently allows any key from
`string_to_type_lut` to be used as a string literal type annotation.

**Test Plan**
Existing unit tests (most notably
`TestClassType.test_self_referential_method` which tests the main
feature, self-referential class type annotations, that make use of
string literal type annotations).

**Fixes**
This commit fixes #47570.

[ghstack-poisoned]