updates HEAP_SIZE to be configurable for embedded alloc #407

Job	Run time
Build SDK	1m 39s
Build SDK (nanos)	2m 19s
Build SDK (nanox)	2m 19s
Run static analysis for cargo-ledger	1m 31s
Build SDK (nanosplus)	2m 16s
Run static analysis (nanos, include_gif)	1m 22s
Build SDK (stax)	2m 19s
Run static analysis (nanos, testmacro)	1m 16s
Check code formatting	1m 12s
Build SDK (flex)	2m 23s
Run static analysis (nanos, ledger_secure_sdk_sys)	1m 47s
Run static analysis (nanos, ledger_device_sdk)	2m 17s
Run static analysis (nanox, include_gif)	1m 25s
Run unit and integration tests (nanos)	2m 49s
Run static analysis (nanox, testmacro)	1m 12s
Run unit and integration tests (nanox)	2m 29s
Run static analysis (nanox, ledger_secure_sdk_sys)	1m 53s
Run unit and integration tests (nanosplus)	2m 34s
Run unit and integration tests (stax)	2m 40s
Run static analysis (nanox, ledger_device_sdk)	2m 14s
Run unit and integration tests (flex)	2m 38s
Run static analysis (nanosplus, include_gif)	1m 22s
Run static analysis (nanosplus, testmacro)	1m 16s
Run static analysis (nanosplus, ledger_secure_sdk_sys)	1m 47s
Run static analysis (nanosplus, ledger_device_sdk)	2m 14s
Run static analysis (stax, include_gif)	1m 25s
Run static analysis (stax, testmacro)	1m 12s
Run static analysis (stax, ledger_secure_sdk_sys)	1m 56s
Run static analysis (stax, ledger_device_sdk)	2m 18s
Run static analysis (flex, include_gif)	1m 23s
Run static analysis (flex, testmacro)	1m 16s
Run static analysis (flex, ledger_secure_sdk_sys)	1m 56s
Run static analysis (flex, ledger_device_sdk)	2m 28s
	1h 3m 7s

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