feat: Make executors_file_path optional and use a default value if None

--- don't change below this line ---
ENG-4088 Took 4 minutes

Took 59 seconds

src/encoding/evm/constants.rs

@@ -0,0 +1 @@
+pub const DEFAULT_EXECUTORS_FILE_PATH: &str = "src/encoding/config/executor_addresses.json";

src/encoding/evm/strategy_encoder/strategy_encoder_registry.rs

@@ -3,6 +3,7 @@ use std::collections::HashMap;
 use crate::encoding::{
     errors::EncodingError,
     evm::{
+        constants::DEFAULT_EXECUTORS_FILE_PATH,
         strategy_encoder::strategy_encoders::{ExecutorStrategyEncoder, SplitSwapStrategyEncoder},
         swap_encoder::swap_encoder_registry::SwapEncoderRegistry,
     },
@@ -22,10 +23,13 @@ pub struct EVMStrategyEncoderRegistry {
 impl StrategyEncoderRegistry for EVMStrategyEncoderRegistry {
     fn new(
         chain: Chain,
-        executors_file_path: &str,
+        executors_file_path: Option<&str>,
         signer_pk: Option<String>,
     ) -> Result<Self, EncodingError> {
-        let swap_encoder_registry = SwapEncoderRegistry::new(executors_file_path, chain.clone())?;
+        let swap_encoder_registry = SwapEncoderRegistry::new(
+            executors_file_path.unwrap_or(DEFAULT_EXECUTORS_FILE_PATH),
+            chain.clone(),
+        )?;
 
         let mut strategies: HashMap<String, Box<dyn StrategyEncoder>> = HashMap::new();
         strategies.insert(

src/encoding/evm/tycho_encoder.rs

@@ -169,7 +169,7 @@ mod tests {
     impl StrategyEncoderRegistry for MockStrategyRegistry {
         fn new(
             _chain: Chain,
-            _executors_file_path: &str,
+            _executors_file_path: Option<&str>,
             _signer_pk: Option<String>,
         ) -> Result<MockStrategyRegistry, EncodingError> {
             Ok(Self { strategy: Box::new(MockStrategy) })
@@ -205,7 +205,7 @@ mod tests {
     }
 
     fn get_mocked_tycho_encoder() -> EVMTychoEncoder<MockStrategyRegistry> {
-        let strategy_registry = MockStrategyRegistry::new(eth_chain(), "", None).unwrap();
+        let strategy_registry = MockStrategyRegistry::new(eth_chain(), None, None).unwrap();
         EVMTychoEncoder::new(
             strategy_registry,
             "0x1234567890abcdef1234567890abcdef12345678".to_string(),